path: root/sql/table.cc

/* Copyright (c) 2000, 2017, Oracle and/or its affiliates.
   Copyright (c) 2008, 2018, MariaDB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1335  USA */


/* Some general useful functions */

#include <my_global.h>                 /* NO_EMBEDDED_ACCESS_CHECKS */
#include "sql_priv.h"
#include "table.h"
#include "key.h"                                // find_ref_key
#include "sql_table.h"                          // build_table_filename,
                                                // primary_key_name
#include "sql_parse.h"                          // free_items
#include "strfunc.h"                            // unhex_type2
#include "sql_partition.h"       // mysql_unpack_partition,
                                 // fix_partition_func, partition_info
#include "sql_acl.h"             // *_ACL, acl_getroot_no_password
#include "sql_base.h"
#include "create_options.h"
#include "sql_trigger.h"
#include <m_ctype.h>
#include "my_md5.h"
#include "my_bit.h"
#include "sql_select.h"
#include "sql_derived.h"
#include "sql_statistics.h"
#include "discover.h"
#include "mdl.h"                 // MDL_wait_for_graph_visitor
#include "sql_view.h"
#include "rpl_filter.h"
#include "sql_cte.h"

/* For MySQL 5.7 virtual fields */
#define MYSQL57_GENERATED_FIELD 128
#define MYSQL57_GCOL_HEADER_SIZE 4

static Virtual_column_info * unpack_vcol_info_from_frm(THD *, MEM_ROOT *,
              TABLE *, String *, Virtual_column_info **, bool *);
static bool check_vcol_forward_refs(Field *, Virtual_column_info *);

/* INFORMATION_SCHEMA name */
LEX_STRING INFORMATION_SCHEMA_NAME= {C_STRING_WITH_LEN("information_schema")};

/* PERFORMANCE_SCHEMA name */
LEX_STRING PERFORMANCE_SCHEMA_DB_NAME= {C_STRING_WITH_LEN("performance_schema")};

/* MYSQL_SCHEMA name */
LEX_STRING MYSQL_SCHEMA_NAME= {C_STRING_WITH_LEN("mysql")};

/* GENERAL_LOG name */
LEX_STRING GENERAL_LOG_NAME= {C_STRING_WITH_LEN("general_log")};

/* SLOW_LOG name */
LEX_STRING SLOW_LOG_NAME= {C_STRING_WITH_LEN("slow_log")};

/* 
  Keyword added as a prefix when parsing the defining expression for a
  virtual column read from the column definition saved in the frm file
*/
static LEX_STRING parse_vcol_keyword= { C_STRING_WITH_LEN("PARSE_VCOL_EXPR ") };

static int64 last_table_id;

	/* Functions defined in this file */

static bool fix_type_pointers(const char ***typelib_value_names,
                              uint **typelib_value_lengths,
                              TYPELIB *point_to_type, uint types,
                              char *names, size_t names_length);

static uint find_field(Field **fields, uchar *record, uint start, uint length);

inline bool is_system_table_name(const char *name, uint length);

/**************************************************************************
  Object_creation_ctx implementation.
**************************************************************************/

Object_creation_ctx *Object_creation_ctx::set_n_backup(THD *thd)
{
  Object_creation_ctx *backup_ctx;
  DBUG_ENTER("Object_creation_ctx::set_n_backup");

  backup_ctx= create_backup_ctx(thd);
  change_env(thd);

  DBUG_RETURN(backup_ctx);
}

void Object_creation_ctx::restore_env(THD *thd, Object_creation_ctx *backup_ctx)
{
  if (!backup_ctx)
    return;

  backup_ctx->change_env(thd);

  delete backup_ctx;
}

/**************************************************************************
  Default_object_creation_ctx implementation.
**************************************************************************/

Default_object_creation_ctx::Default_object_creation_ctx(THD *thd)
  : m_client_cs(thd->variables.character_set_client),
    m_connection_cl(thd->variables.collation_connection)
{ }

Default_object_creation_ctx::Default_object_creation_ctx(
  CHARSET_INFO *client_cs, CHARSET_INFO *connection_cl)
  : m_client_cs(client_cs),
    m_connection_cl(connection_cl)
{ }

Object_creation_ctx *
Default_object_creation_ctx::create_backup_ctx(THD *thd) const
{
  return new Default_object_creation_ctx(thd);
}

void Default_object_creation_ctx::change_env(THD *thd) const
{
  thd->update_charset(m_client_cs, m_connection_cl);
}

/**************************************************************************
  View_creation_ctx implementation.
**************************************************************************/

View_creation_ctx *View_creation_ctx::create(THD *thd)
{
  View_creation_ctx *ctx= new (thd->mem_root) View_creation_ctx(thd);

  return ctx;
}

/*************************************************************************/

View_creation_ctx * View_creation_ctx::create(THD *thd,
                                              TABLE_LIST *view)
{
  View_creation_ctx *ctx= new (thd->mem_root) View_creation_ctx(thd);

  /* Throw a warning if there is NULL cs name. */

  if (!view->view_client_cs_name.str ||
      !view->view_connection_cl_name.str)
  {
    push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
                        ER_VIEW_NO_CREATION_CTX,
                        ER_THD(thd, ER_VIEW_NO_CREATION_CTX),
                        (const char *) view->db,
                        (const char *) view->table_name);

    ctx->m_client_cs= system_charset_info;
    ctx->m_connection_cl= system_charset_info;

    return ctx;
  }

  /* Resolve cs names. Throw a warning if there is unknown cs name. */

  bool invalid_creation_ctx;

  invalid_creation_ctx= resolve_charset(view->view_client_cs_name.str,
                                        system_charset_info,
                                        &ctx->m_client_cs);

  invalid_creation_ctx= resolve_collation(view->view_connection_cl_name.str,
                                          system_charset_info,
                                          &ctx->m_connection_cl) ||
                        invalid_creation_ctx;

  if (invalid_creation_ctx)
  {
    sql_print_warning("View '%s'.'%s': there is unknown charset/collation "
                      "names (client: '%s'; connection: '%s').",
                      (const char *) view->db,
                      (const char *) view->table_name,
                      (const char *) view->view_client_cs_name.str,
                      (const char *) view->view_connection_cl_name.str);

    push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
                        ER_VIEW_INVALID_CREATION_CTX,
                        ER_THD(thd, ER_VIEW_INVALID_CREATION_CTX),
                        (const char *) view->db,
                        (const char *) view->table_name);
  }

  return ctx;
}

/*************************************************************************/

/* Get column name from column hash */

static uchar *get_field_name(Field **buff, size_t *length,
                             my_bool not_used __attribute__((unused)))
{
  *length= (uint) strlen((*buff)->field_name);
  return (uchar*) (*buff)->field_name;
}


/*
  Returns pointer to '.frm' extension of the file name.

  SYNOPSIS
    fn_rext()
    name       file name

  DESCRIPTION
    Checks file name part starting with the rightmost '.' character,
    and returns it if it is equal to '.frm'. 

  TODO
    It is a good idea to get rid of this function modifying the code
    to garantee that the functions presently calling fn_rext() always
    get arguments in the same format: either with '.frm' or without '.frm'.

  RETURN VALUES
    Pointer to the '.frm' extension. If there is no extension,
    or extension is not '.frm', pointer at the end of file name.
*/

char *fn_rext(char *name)
{
  char *res= strrchr(name, '.');
  if (res && !strcmp(res, reg_ext))
    return res;
  return name + strlen(name);
}

TABLE_CATEGORY get_table_category(const LEX_STRING *db, const LEX_STRING *name)
{
  DBUG_ASSERT(db != NULL);
  DBUG_ASSERT(name != NULL);

  if (is_infoschema_db(db->str, db->length))
    return TABLE_CATEGORY_INFORMATION;

  if ((db->length == PERFORMANCE_SCHEMA_DB_NAME.length) &&
      (my_strcasecmp(system_charset_info,
                     PERFORMANCE_SCHEMA_DB_NAME.str,
                     db->str) == 0))
    return TABLE_CATEGORY_PERFORMANCE;

  if ((db->length == MYSQL_SCHEMA_NAME.length) &&
      (my_strcasecmp(system_charset_info,
                     MYSQL_SCHEMA_NAME.str,
                     db->str) == 0))
  {
    if (is_system_table_name(name->str, name->length))
      return TABLE_CATEGORY_SYSTEM;

    if ((name->length == GENERAL_LOG_NAME.length) &&
        (my_strcasecmp(system_charset_info,
                       GENERAL_LOG_NAME.str,
                       name->str) == 0))
      return TABLE_CATEGORY_LOG;

    if ((name->length == SLOW_LOG_NAME.length) &&
        (my_strcasecmp(system_charset_info,
                       SLOW_LOG_NAME.str,
                       name->str) == 0))
      return TABLE_CATEGORY_LOG;
  }

  return TABLE_CATEGORY_USER;
}


/*
  Allocate and setup a TABLE_SHARE structure

  SYNOPSIS
    alloc_table_share()
    db                  Database name
    table_name          Table name
    key			Table cache key (db \0 table_name \0...)
    key_length		Length of key

  RETURN
    0  Error (out of memory)
    #  Share
*/

TABLE_SHARE *alloc_table_share(const char *db, const char *table_name,
                               const char *key, uint key_length)
{
  MEM_ROOT mem_root;
  TABLE_SHARE *share;
  char *key_buff, *path_buff;
  char path[FN_REFLEN];
  uint path_length;
  DBUG_ENTER("alloc_table_share");
  DBUG_PRINT("enter", ("table: '%s'.'%s'", db, table_name));

  path_length= build_table_filename(path, sizeof(path) - 1,
                                    db, table_name, "", 0);
  init_sql_alloc(&mem_root, TABLE_ALLOC_BLOCK_SIZE, 0, MYF(0));
  if (multi_alloc_root(&mem_root,
                       &share, sizeof(*share),
                       &key_buff, key_length,
                       &path_buff, path_length + 1,
                       NULL))
  {
    bzero((char*) share, sizeof(*share));

    share->set_table_cache_key(key_buff, key, key_length);

    share->path.str= path_buff;
    share->path.length= path_length;
    strmov(share->path.str, path);
    share->normalized_path.str=    share->path.str;
    share->normalized_path.length= path_length;
    share->table_category= get_table_category(& share->db, & share->table_name);
    share->open_errno= ENOENT;
    /* The following will be fixed in open_table_from_share */
    share->cached_row_logging_check= 1;

    init_sql_alloc(&share->stats_cb.mem_root, TABLE_ALLOC_BLOCK_SIZE, 0, MYF(0));

    memcpy((char*) &share->mem_root, (char*) &mem_root, sizeof(mem_root));
    mysql_mutex_init(key_TABLE_SHARE_LOCK_share,
                     &share->LOCK_share, MY_MUTEX_INIT_SLOW);
    mysql_mutex_init(key_TABLE_SHARE_LOCK_ha_data,
                     &share->LOCK_ha_data, MY_MUTEX_INIT_FAST);

    DBUG_EXECUTE_IF("simulate_big_table_id",
                    if (last_table_id < UINT_MAX32)
                      last_table_id= UINT_MAX32 - 1;);
    /*
      There is one reserved number that cannot be used. Remember to
      change this when 6-byte global table id's are introduced.
    */
    do
    {
      share->table_map_id=(ulong) my_atomic_add64_explicit(&last_table_id, 1,
                                                    MY_MEMORY_ORDER_RELAXED);
    } while (unlikely(share->table_map_id == ~0UL ||
                      share->table_map_id == 0));
  }
  DBUG_RETURN(share);
}


/*
  Initialize share for temporary tables

  SYNOPSIS
    init_tmp_table_share()
    thd         thread handle
    share	Share to fill
    key		Table_cache_key, as generated from tdc_create_key.
		must start with db name.
    key_length	Length of key
    table_name	Table name
    path	Path to file (possible in lower case) without .frm

  NOTES
    This is different from alloc_table_share() because temporary tables
    don't have to be shared between threads or put into the table def
    cache, so we can do some things notable simpler and faster

    If table is not put in thd->temporary_tables (happens only when
    one uses OPEN TEMPORARY) then one can specify 'db' as key and
    use key_length= 0 as neither table_cache_key or key_length will be used).
*/

void init_tmp_table_share(THD *thd, TABLE_SHARE *share, const char *key,
                          uint key_length, const char *table_name,
                          const char *path)
{
  DBUG_ENTER("init_tmp_table_share");
  DBUG_PRINT("enter", ("table: '%s'.'%s'", key, table_name));

  bzero((char*) share, sizeof(*share));
  /*
    This can't be MY_THREAD_SPECIFIC for slaves as they are freed
    during cleanup() from Relay_log_info::close_temporary_tables()
  */
  init_sql_alloc(&share->mem_root, TABLE_ALLOC_BLOCK_SIZE, 0, 
                 MYF(thd->slave_thread ? 0 : MY_THREAD_SPECIFIC));
  share->table_category=         TABLE_CATEGORY_TEMPORARY;
  share->tmp_table=              INTERNAL_TMP_TABLE;
  share->db.str=                 (char*) key;
  share->db.length=		 strlen(key);
  share->table_cache_key.str=    (char*) key;
  share->table_cache_key.length= key_length;
  share->table_name.str=         (char*) table_name;
  share->table_name.length=      strlen(table_name);
  share->path.str=               (char*) path;
  share->normalized_path.str=    (char*) path;
  share->path.length= share->normalized_path.length= strlen(path);
  share->frm_version= 		 FRM_VER_CURRENT;

  share->cached_row_logging_check= 0;           // No row logging

  /*
    table_map_id is also used for MERGE tables to suppress repeated
    compatibility checks.
  */
  share->table_map_id= (ulong) thd->query_id;
  DBUG_VOID_RETURN;
}


/**
  Release resources (plugins) used by the share and free its memory.
  TABLE_SHARE is self-contained -- it's stored in its own MEM_ROOT.
  Free this MEM_ROOT.
*/

void TABLE_SHARE::destroy()
{
  uint idx;
  KEY *info_it;
  DBUG_ENTER("TABLE_SHARE::destroy");
  DBUG_PRINT("info", ("db: %s table: %s", db.str, table_name.str));

  if (ha_share)
  {
    delete ha_share;
    ha_share= NULL;                             // Safety
  }

  delete_stat_values_for_table_share(this);
  free_root(&stats_cb.mem_root, MYF(0));
  stats_cb.stats_can_be_read= FALSE;
  stats_cb.stats_is_read= FALSE;
  stats_cb.histograms_can_be_read= FALSE;
  stats_cb.histograms_are_read= FALSE;

  /* The mutexes are initialized only for shares that are part of the TDC */
  if (tmp_table == NO_TMP_TABLE)
  {
    mysql_mutex_destroy(&LOCK_share);
    mysql_mutex_destroy(&LOCK_ha_data);
  }
  my_hash_free(&name_hash);

  plugin_unlock(NULL, db_plugin);
  db_plugin= NULL;

  /* Release fulltext parsers */
  info_it= key_info;
  for (idx= keys; idx; idx--, info_it++)
  {
    if (info_it->flags & HA_USES_PARSER)
    {
      plugin_unlock(NULL, info_it->parser);
      info_it->flags= 0;
    }
  }

#ifdef WITH_PARTITION_STORAGE_ENGINE
  plugin_unlock(NULL, default_part_plugin);
#endif /* WITH_PARTITION_STORAGE_ENGINE */

  PSI_CALL_release_table_share(m_psi);

  /*
    Make a copy since the share is allocated in its own root,
    and free_root() updates its argument after freeing the memory.
  */
  MEM_ROOT own_root= mem_root;
  free_root(&own_root, MYF(0));
  DBUG_VOID_RETURN;
}

/*
  Free table share and memory used by it

  SYNOPSIS
    free_table_share()
    share		Table share
*/

void free_table_share(TABLE_SHARE *share)
{
  DBUG_ENTER("free_table_share");
  DBUG_PRINT("enter", ("table: %s.%s", share->db.str, share->table_name.str));
  share->destroy();
  DBUG_VOID_RETURN;
}


/**
  Return TRUE if a table name matches one of the system table names.
  Currently these are:

  help_category, help_keyword, help_relation, help_topic,
  proc, event
  time_zone, time_zone_leap_second, time_zone_name, time_zone_transition,
  time_zone_transition_type

  This function trades accuracy for speed, so may return false
  positives. Presumably mysql.* database is for internal purposes only
  and should not contain user tables.
*/

inline bool is_system_table_name(const char *name, uint length)
{
  CHARSET_INFO *ci= system_charset_info;

  return (
          /* mysql.proc table */
          (length == 4 &&
           my_tolower(ci, name[0]) == 'p' && 
           my_tolower(ci, name[1]) == 'r' &&
           my_tolower(ci, name[2]) == 'o' &&
           my_tolower(ci, name[3]) == 'c') ||

          (length > 4 &&
           (
            /* one of mysql.help* tables */
            (my_tolower(ci, name[0]) == 'h' &&
             my_tolower(ci, name[1]) == 'e' &&
             my_tolower(ci, name[2]) == 'l' &&
             my_tolower(ci, name[3]) == 'p') ||

            /* one of mysql.time_zone* tables */
            (my_tolower(ci, name[0]) == 't' &&
             my_tolower(ci, name[1]) == 'i' &&
             my_tolower(ci, name[2]) == 'm' &&
             my_tolower(ci, name[3]) == 'e') ||

            /* one of mysql.*_stat tables, but not mysql.innodb* tables*/
            ((my_tolower(ci, name[length-5]) == 's' &&
              my_tolower(ci, name[length-4]) == 't' &&
              my_tolower(ci, name[length-3]) == 'a' &&
              my_tolower(ci, name[length-2]) == 't' &&
              my_tolower(ci, name[length-1]) == 's') &&
             !(my_tolower(ci, name[0]) == 'i' &&
               my_tolower(ci, name[1]) == 'n' &&
               my_tolower(ci, name[2]) == 'n' &&
               my_tolower(ci, name[3]) == 'o')) ||

            /* mysql.event table */
            (my_tolower(ci, name[0]) == 'e' &&
             my_tolower(ci, name[1]) == 'v' &&
             my_tolower(ci, name[2]) == 'e' &&
             my_tolower(ci, name[3]) == 'n' &&
             my_tolower(ci, name[4]) == 't')
            )
           )
         );
}


/*
  Read table definition from a binary / text based .frm file
  
  SYNOPSIS
  open_table_def()
  thd		  Thread handler
  share		Fill this with table definition
  flags	  Bit mask of the following flags: OPEN_VIEW

  NOTES
    This function is called when the table definition is not cached in
    table definition cache
    The data is returned in 'share', which is allocated by
    alloc_table_share().. The code assumes that share is initialized.
*/

enum open_frm_error open_table_def(THD *thd, TABLE_SHARE *share, uint flags)
{
  bool error_given= false;
  File file;
  uchar *buf;
  uchar head[FRM_HEADER_SIZE];
  char	path[FN_REFLEN];
  size_t frmlen, read_length;
  uint length;
  DBUG_ENTER("open_table_def");
  DBUG_PRINT("enter", ("table: '%s'.'%s'  path: '%s'", share->db.str,
                       share->table_name.str, share->normalized_path.str));

  share->error= OPEN_FRM_OPEN_ERROR;

  length=(uint) (strxmov(path, share->normalized_path.str, reg_ext, NullS) -
                 path);
  if (flags & GTS_FORCE_DISCOVERY)
  {
    DBUG_ASSERT(flags & GTS_TABLE);
    DBUG_ASSERT(flags & GTS_USE_DISCOVERY);
    mysql_file_delete_with_symlink(key_file_frm, path, "", MYF(0));
    file= -1;
  }
  else
    file= mysql_file_open(key_file_frm, path, O_RDONLY | O_SHARE, MYF(0));

  if (file < 0)
  {
    if ((flags & GTS_TABLE) && (flags & GTS_USE_DISCOVERY))
    {
      ha_discover_table(thd, share);
      error_given= true;
    }
    goto err_not_open;
  }

  if (mysql_file_read(file, head, sizeof(head), MYF(MY_NABP)))
  {
    share->error = my_errno == HA_ERR_FILE_TOO_SHORT
                      ? OPEN_FRM_CORRUPTED : OPEN_FRM_READ_ERROR;
    goto err;
  }

  if (memcmp(head, STRING_WITH_LEN("TYPE=VIEW\n")) == 0)
  {
    share->is_view= 1;
    if (flags & GTS_VIEW)
    {
      LEX_STRING pathstr= { path, length };
      /*
        Create view file parser and hold it in TABLE_SHARE member
        view_def.
      */
      share->view_def= sql_parse_prepare(&pathstr, &share->mem_root, true);
      if (!share->view_def)
        share->error= OPEN_FRM_ERROR_ALREADY_ISSUED;
      else
        share->error= OPEN_FRM_OK;
    }
    else
      share->error= OPEN_FRM_NOT_A_TABLE;
    goto err;
  }
  if (!is_binary_frm_header(head))
  {
    /* No handling of text based files yet */
    share->error = OPEN_FRM_CORRUPTED;
    goto err;
  }
  if (!(flags & GTS_TABLE))
  {
    share->error = OPEN_FRM_NOT_A_VIEW;
    goto err;
  }

  frmlen= uint4korr(head+10);
  set_if_smaller(frmlen, FRM_MAX_SIZE); // safety

  if (!(buf= (uchar*)my_malloc(frmlen, MYF(MY_THREAD_SPECIFIC|MY_WME))))
    goto err;

  memcpy(buf, head, sizeof(head));

  read_length= mysql_file_read(file, buf + sizeof(head),
                               frmlen - sizeof(head), MYF(MY_WME));
  if (read_length == 0 || read_length == (size_t)-1)
  {
    share->error = OPEN_FRM_READ_ERROR;
    my_free(buf);
    goto err;
  }
  mysql_file_close(file, MYF(MY_WME));

  frmlen= read_length + sizeof(head);

  share->init_from_binary_frm_image(thd, false, buf, frmlen);
  error_given= true; // init_from_binary_frm_image has already called my_error()
  my_free(buf);

  goto err_not_open;

err:
  mysql_file_close(file, MYF(MY_WME));

err_not_open:
  if (share->error && !error_given)
  {
    share->open_errno= my_errno;
    open_table_error(share, share->error, share->open_errno);
  }

  DBUG_RETURN(share->error);
}

static bool create_key_infos(const uchar *strpos, const uchar *frm_image_end,
                             uint keys, KEY *keyinfo,
                             uint new_frm_ver, uint &ext_key_parts,
                             TABLE_SHARE *share, uint len,
                             KEY *first_keyinfo,
                             LEX_STRING *keynames)
{
  uint i, j, n_length;
  KEY_PART_INFO *key_part= NULL;
  ulong *rec_per_key= NULL;
  KEY_PART_INFO *first_key_part= NULL;
  uint first_key_parts= 0;

  if (!keys)
  {  
    if (!(keyinfo = (KEY*) alloc_root(&share->mem_root, len)))
      return 1;
    bzero((char*) keyinfo, len);
    key_part= reinterpret_cast<KEY_PART_INFO*> (keyinfo);
  }

  /*
    If share->use_ext_keys is set to TRUE we assume that any key
    can be extended by the components of the primary key whose
    definition is read first from the frm file.
    For each key only those fields of the assumed primary key are
    added that are not included in the proper key definition. 
    If after all it turns out that there is no primary key the
    added components are removed from each key.

    When in the future we support others schemes of extending of
    secondary keys with components of the primary key we'll have
    to change the type of this flag for an enumeration type.
  */

  for (i=0 ; i < keys ; i++, keyinfo++)
  {
    if (new_frm_ver >= 3)
    {
      if (strpos + 8 >= frm_image_end)
        return 1;
      keyinfo->flags=	   (uint) uint2korr(strpos) ^ HA_NOSAME;
      keyinfo->key_length= (uint) uint2korr(strpos+2);
      keyinfo->user_defined_key_parts=  (uint) strpos[4];
      keyinfo->algorithm=  (enum ha_key_alg) strpos[5];
      keyinfo->block_size= uint2korr(strpos+6);
      strpos+=8;
    }
    else
    {
      if (strpos + 4 >= frm_image_end)
        return 1;
      keyinfo->flags=	 ((uint) strpos[0]) ^ HA_NOSAME;
      keyinfo->key_length= (uint) uint2korr(strpos+1);
      keyinfo->user_defined_key_parts=  (uint) strpos[3];
      keyinfo->algorithm= HA_KEY_ALG_UNDEF;
      strpos+=4;
    }

    if (i == 0)
    {
      ext_key_parts+= (share->use_ext_keys ? first_keyinfo->user_defined_key_parts*(keys-1) : 0); 
      n_length=keys * sizeof(KEY) + ext_key_parts * sizeof(KEY_PART_INFO);
      if (!(keyinfo= (KEY*) alloc_root(&share->mem_root,
				       n_length + len)))
        return 1;
      bzero((char*) keyinfo,n_length);
      share->key_info= keyinfo;
      key_part= reinterpret_cast<KEY_PART_INFO*> (keyinfo + keys);

      if (!(rec_per_key= (ulong*) alloc_root(&share->mem_root,
                                             sizeof(ulong) * ext_key_parts)))
        return 1;
      first_key_part= key_part;
      first_key_parts= first_keyinfo->user_defined_key_parts;
      keyinfo->flags= first_keyinfo->flags;
      keyinfo->key_length= first_keyinfo->key_length;
      keyinfo->user_defined_key_parts= first_keyinfo->user_defined_key_parts;
      keyinfo->algorithm= first_keyinfo->algorithm;
      if (new_frm_ver >= 3)
        keyinfo->block_size= first_keyinfo->block_size;
    }

    keyinfo->key_part=	 key_part;
    keyinfo->rec_per_key= rec_per_key;
    for (j=keyinfo->user_defined_key_parts ; j-- ; key_part++)
    {
      if (strpos + (new_frm_ver >= 1 ? 9 : 7) >= frm_image_end)
        return 1;
      *rec_per_key++=0;
      key_part->fieldnr=	(uint16) (uint2korr(strpos) & FIELD_NR_MASK);
      key_part->offset= (uint) uint2korr(strpos+2)-1;
      key_part->key_type=	(uint) uint2korr(strpos+5);
      // key_part->field=	(Field*) 0;	// Will be fixed later
      if (new_frm_ver >= 1)
      {
	key_part->key_part_flag= *(strpos+4);
	key_part->length=	(uint) uint2korr(strpos+7);
	strpos+=9;
      }
      else
      {
	key_part->length=	*(strpos+4);
	key_part->key_part_flag=0;
	if (key_part->length > 128)
	{
	  key_part->length&=127;		/* purecov: inspected */
	  key_part->key_part_flag=HA_REVERSE_SORT; /* purecov: inspected */
	}
	strpos+=7;
      }
      key_part->store_length=key_part->length;
    }

    /*
      Add primary key to end of extended keys for non unique keys for
      storage engines that supports it.
    */
    keyinfo->ext_key_parts= keyinfo->user_defined_key_parts;
    keyinfo->ext_key_flags= keyinfo->flags;
    keyinfo->ext_key_part_map= 0;
    if (share->use_ext_keys && i && !(keyinfo->flags & HA_NOSAME))
    {
      for (j= 0; 
           j < first_key_parts && keyinfo->ext_key_parts < MAX_REF_PARTS;
           j++)
      {
        uint key_parts= keyinfo->user_defined_key_parts;
        KEY_PART_INFO* curr_key_part= keyinfo->key_part;
        KEY_PART_INFO* curr_key_part_end= curr_key_part+key_parts;
        for ( ; curr_key_part < curr_key_part_end; curr_key_part++)
        {
          if (curr_key_part->fieldnr == first_key_part[j].fieldnr)
            break;
        }
        if (curr_key_part == curr_key_part_end)
        {
          *key_part++= first_key_part[j];
          *rec_per_key++= 0;
          keyinfo->ext_key_parts++;
          keyinfo->ext_key_part_map|= 1 << j;
        }
      }
      if (j == first_key_parts)
        keyinfo->ext_key_flags= keyinfo->flags | HA_EXT_NOSAME;
    }
    share->ext_key_parts+= keyinfo->ext_key_parts;  
  }
  keynames->str= (char*) key_part;
  keynames->length= strnmov(keynames->str, (char *) strpos,
                            frm_image_end - strpos) - keynames->str;
  strpos+= keynames->length;
  if (*strpos++) // key names are \0-terminated
    return 1;
  keynames->length++; // Include '\0', to make fix_type_pointers() happy.

  //reading index comments
  for (keyinfo= share->key_info, i=0; i < keys; i++, keyinfo++)
  {
    if (keyinfo->flags & HA_USES_COMMENT)
    {
      if (strpos + 2 >= frm_image_end)
        return 1;
      keyinfo->comment.length= uint2korr(strpos);
      strpos+= 2;

      if (strpos + keyinfo->comment.length >= frm_image_end)
        return 1;
      keyinfo->comment.str= strmake_root(&share->mem_root, (char*) strpos,
                                         keyinfo->comment.length);
      strpos+= keyinfo->comment.length;
    } 
    DBUG_ASSERT(MY_TEST(keyinfo->flags & HA_USES_COMMENT) ==
                (keyinfo->comment.length > 0));
  }

  share->keys= keys; // do it *after* all key_info's are initialized

  return 0;
}


/** ensures that the enum value (read from frm) is within limits

    if not - issues a warning and resets the value to 0
    (that is, 0 is assumed to be a default value)
*/

static uint enum_value_with_check(THD *thd, TABLE_SHARE *share,
                                  const char *name, uint value, uint limit)
{
  if (value < limit)
    return value;

  sql_print_warning("%s.frm: invalid value %d for the field %s",
                share->normalized_path.str, value, name);
  return 0;
}


/**
   Check if a collation has changed number

   @param mysql_version
   @param current collation number

   @retval new collation number (same as current collation number of no change)
*/

static uint upgrade_collation(ulong mysql_version, uint cs_number)
{
  if (mysql_version >= 50300 && mysql_version <= 50399)
  {
    switch (cs_number) {
    case 149: return MY_PAGE2_COLLATION_ID_UCS2;   // ucs2_crotian_ci
    case 213: return MY_PAGE2_COLLATION_ID_UTF8;   // utf8_crotian_ci
    }
  }
  if ((mysql_version >= 50500 && mysql_version <= 50599) ||
      (mysql_version >= 100000 && mysql_version <= 100005))
  {
    switch (cs_number) {
    case 149: return MY_PAGE2_COLLATION_ID_UCS2;   // ucs2_crotian_ci
    case 213: return MY_PAGE2_COLLATION_ID_UTF8;   // utf8_crotian_ci
    case 214: return MY_PAGE2_COLLATION_ID_UTF32;  // utf32_croatian_ci
    case 215: return MY_PAGE2_COLLATION_ID_UTF16;  // utf16_croatian_ci
    case 245: return MY_PAGE2_COLLATION_ID_UTF8MB4;// utf8mb4_croatian_ci
    }
  }
  return cs_number;
}


/*
  In MySQL 5.7 the null bits for not stored virtual fields are last.
  Calculate the position for these bits
*/

static void mysql57_calculate_null_position(TABLE_SHARE *share,
                                            uchar **null_pos,
                                            uint *null_bit_pos,
                                            const uchar *strpos,
                                            const uchar *vcol_screen_pos)
{
  uint field_pack_length= 17;

  for (uint i=0 ; i < share->fields; i++, strpos+= field_pack_length)
  {
    uint field_length, pack_flag;
    enum_field_types field_type;

    if ((strpos[10] & MYSQL57_GENERATED_FIELD))
    {
      /* Skip virtual (not stored) generated field */
      bool stored_in_db= vcol_screen_pos[3];
      vcol_screen_pos+= (uint2korr(vcol_screen_pos + 1) +
                         MYSQL57_GCOL_HEADER_SIZE);
      if (! stored_in_db)
        continue;
    }
    field_length= uint2korr(strpos+3);
    pack_flag=    uint2korr(strpos+8);
    field_type=   (enum_field_types) (uint) strpos[13];
    if (field_type == MYSQL_TYPE_BIT && !f_bit_as_char(pack_flag))
    {
      if (((*null_bit_pos)+= field_length & 7) > 7)
      {
        (*null_pos)++;
        (*null_bit_pos)-= 8;
      }
    }
    if (f_maybe_null(pack_flag))
    {
      if (!((*null_bit_pos)= ((*null_bit_pos) + 1) & 7))
        (*null_pos)++;
    }
  }
}


/** Parse TABLE_SHARE::vcol_defs

  unpack_vcol_info_from_frm
  5.7
    byte 1      = 1
    byte 2,3    = expr length
    byte 4      = stored_in_db
    expression
  10.1-
    byte 1     = 1 | 2
    byte 2     = sql_type       ; but  TABLE::init_from_binary_frm_image()
    byte 3     = stored_in_db   ; has put expr_length here
    [byte 4]   = optional interval_id for sql_type (if byte 1 == 2)
    expression
  10.2+
    byte 1     = type
    byte 2,3   = field_number
    byte 4,5   = length of expression
    byte 6     = length of name
    name
    expression
*/
bool parse_vcol_defs(THD *thd, MEM_ROOT *mem_root, TABLE *table,
                     bool *error_reported, vcol_init_mode mode)
{
  CHARSET_INFO *save_character_set_client= thd->variables.character_set_client;
  CHARSET_INFO *save_collation= thd->variables.collation_connection;
  Query_arena  *backup_stmt_arena_ptr= thd->stmt_arena;
  const uchar *pos= table->s->vcol_defs.str;
  const uchar *end= pos + table->s->vcol_defs.length;
  Field **field_ptr= table->field - 1;
  Field **vfield_ptr= table->vfield;
  Field **dfield_ptr= table->default_field;
  Virtual_column_info **check_constraint_ptr= table->check_constraints;
  sql_mode_t saved_mode= thd->variables.sql_mode;
  Query_arena backup_arena;
  Virtual_column_info *vcol= 0;
  StringBuffer<MAX_FIELD_WIDTH> expr_str;
  bool res= 1;
  DBUG_ENTER("parse_vcol_defs");

  if (check_constraint_ptr)
    memcpy(table->check_constraints + table->s->field_check_constraints,
           table->s->check_constraints,
           table->s->table_check_constraints * sizeof(Virtual_column_info*));

  DBUG_ASSERT(table->expr_arena == NULL);
  /*
    We need to use CONVENTIONAL_EXECUTION here to ensure that
    any new items created by fix_fields() are not reverted.
  */
  table->expr_arena= new (alloc_root(mem_root, sizeof(Query_arena)))
                        Query_arena(mem_root, Query_arena::STMT_CONVENTIONAL_EXECUTION);
  if (!table->expr_arena)
    DBUG_RETURN(1);

  thd->set_n_backup_active_arena(table->expr_arena, &backup_arena);
  thd->stmt_arena= table->expr_arena;
  thd->update_charset(&my_charset_utf8mb4_general_ci, table->s->table_charset);
  expr_str.append(&parse_vcol_keyword);
  thd->variables.sql_mode &= ~MODE_NO_BACKSLASH_ESCAPES;

  while (pos < end)
  {
    uint type, expr_length;
    if (table->s->frm_version >= FRM_VER_EXPRESSSIONS)
    {
      uint field_nr, name_length;
      /* see pack_expression() for how data is stored */
      type= pos[0];
      field_nr= uint2korr(pos+1);
      expr_length= uint2korr(pos+3);
      name_length= pos[5];
      pos+= FRM_VCOL_NEW_HEADER_SIZE + name_length;
      field_ptr= table->field + field_nr;
    }
    else
    {
      /*
        see below in ::init_from_binary_frm_image for how data is stored
        in versions below 10.2 (that includes 5.7 too)
      */
      while (*++field_ptr && !(*field_ptr)->vcol_info) /* no-op */;
      if (!*field_ptr)
      {
        open_table_error(table->s, OPEN_FRM_CORRUPTED, 1);
        goto end;
      }
      type= (*field_ptr)->vcol_info->stored_in_db
            ? VCOL_GENERATED_STORED : VCOL_GENERATED_VIRTUAL;
      expr_length= uint2korr(pos+1);
      if (table->s->mysql_version > 50700 && table->s->mysql_version < 100000)
        pos+= 4;                        // MySQL from 5.7
      else
        pos+= pos[0] == 2 ? 4 : 3;      // MariaDB from 5.2 to 10.1
    }

    expr_str.length(parse_vcol_keyword.length);
    expr_str.append((char*)pos, expr_length);
    thd->where= vcol_type_name(static_cast<enum_vcol_info_type>(type));

    switch (type) {
    case VCOL_GENERATED_VIRTUAL:
    case VCOL_GENERATED_STORED:
      vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
                                    &((*field_ptr)->vcol_info), error_reported);
      *(vfield_ptr++)= *field_ptr;
      if (vcol && field_ptr[0]->check_vcol_sql_mode_dependency(thd, mode))
      {
        DBUG_ASSERT(thd->is_error());
        *error_reported= true;
        goto end;
      }
      break;
    case VCOL_DEFAULT:
      vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
                                      &((*field_ptr)->default_value),
                                      error_reported);
      *(dfield_ptr++)= *field_ptr;
      if (vcol && (vcol->flags & (VCOL_NON_DETERMINISTIC | VCOL_SESSION_FUNC)))
        table->s->non_determinstic_insert= true;
      break;
    case VCOL_CHECK_FIELD:
      vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
                                      &((*field_ptr)->check_constraint),
                                      error_reported);
      *check_constraint_ptr++= (*field_ptr)->check_constraint;
      break;
    case VCOL_CHECK_TABLE:
      vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
                                      check_constraint_ptr, error_reported);
      check_constraint_ptr++;
      break;
    }
    if (!vcol)
      goto end;
    pos+= expr_length;
  }

  /* Now, initialize CURRENT_TIMESTAMP fields */
  for (field_ptr= table->field; *field_ptr; field_ptr++)
  {
    Field *field= *field_ptr;
    if (field->has_default_now_unireg_check())
    {
      expr_str.length(parse_vcol_keyword.length);
      expr_str.append(STRING_WITH_LEN("current_timestamp("));
      expr_str.append_ulonglong(field->decimals());
      expr_str.append(')');
      vcol= unpack_vcol_info_from_frm(thd, mem_root, table, &expr_str,
                                      &((*field_ptr)->default_value),
                                      error_reported);
      *(dfield_ptr++)= *field_ptr;
      if (!field->default_value->expr)
        goto end;
    }
    else if (field->has_update_default_function() && !field->default_value)
      *(dfield_ptr++)= *field_ptr;
  }

  if (vfield_ptr)
    *vfield_ptr= 0;

  if (dfield_ptr)
    *dfield_ptr= 0;

  if (check_constraint_ptr)
    *check_constraint_ptr= 0;

  /* Check that expressions aren't referring to not yet initialized fields */
  for (field_ptr= table->field; *field_ptr; field_ptr++)
  {
    Field *field= *field_ptr;
    if (check_vcol_forward_refs(field, field->vcol_info) ||
        check_vcol_forward_refs(field, field->check_constraint) ||
        check_vcol_forward_refs(field, field->default_value))
      goto end;
  }

  res=0;
end:
  thd->restore_active_arena(table->expr_arena, &backup_arena);
  thd->stmt_arena= backup_stmt_arena_ptr;
  if (save_character_set_client)
    thd->update_charset(save_character_set_client, save_collation);
  thd->variables.sql_mode= saved_mode;
  DBUG_RETURN(res);
}

/**
  Read data from a binary .frm file image into a TABLE_SHARE

  @note
  frm bytes at the following offsets are unused in MariaDB 10.0:

  8..9    (used to be the number of "form names")
  28..29  (used to be key_info_length)

  They're still set, for compatibility reasons, but never read.

  42..46 are unused since 5.0 (were for RAID support)
  Also, there're few unused bytes in forminfo.

*/

int TABLE_SHARE::init_from_binary_frm_image(THD *thd, bool write,
                                            const uchar *frm_image,
                                            size_t frm_length)
{
  TABLE_SHARE *share= this;
  uint new_frm_ver, field_pack_length, new_field_pack_flag;
  uint interval_count, interval_parts, read_length, int_length;
  uint total_typelib_value_count;
  uint db_create_options, keys, key_parts, n_length;
  uint com_length, null_bit_pos, UNINIT_VAR(mysql57_vcol_null_bit_pos), bitmap_count;
  uint i;
  bool use_hash, mysql57_null_bits= 0;
  LEX_STRING keynames= {NULL, 0};
  char *names, *comment_pos;
  const uchar *forminfo, *extra2;
  const uchar *frm_image_end = frm_image + frm_length;
  uchar *record, *null_flags, *null_pos, *UNINIT_VAR(mysql57_vcol_null_pos);
  const uchar *disk_buff, *strpos;
  ulong pos, record_offset; 
  ulong rec_buff_length;
  handler *handler_file= 0;
  KEY	*keyinfo;
  KEY_PART_INFO *key_part= NULL;
  Field  **field_ptr, *reg_field;
  const char **interval_array;
  uint *typelib_value_lengths= NULL;
  enum legacy_db_type legacy_db_type;
  my_bitmap_map *bitmaps;
  bool null_bits_are_used;
  uint vcol_screen_length, UNINIT_VAR(options_len);
  uchar *vcol_screen_pos;
  const uchar *options= 0;
  uint UNINIT_VAR(gis_options_len);
  const uchar *gis_options= 0;
  KEY first_keyinfo;
  uint len;
  uint ext_key_parts= 0;
  plugin_ref se_plugin= 0;
  MEM_ROOT *old_root= thd->mem_root;
  Virtual_column_info **table_check_constraints;
  DBUG_ENTER("TABLE_SHARE::init_from_binary_frm_image");

  keyinfo= &first_keyinfo;
  share->ext_key_parts= 0;
  thd->mem_root= &share->mem_root;

  if (write && write_frm_image(frm_image, frm_length))
    goto err;

  if (frm_length < FRM_HEADER_SIZE + FRM_FORMINFO_SIZE)
    goto err;

  share->frm_version= frm_image[2];
  /*
    Check if .frm file created by MySQL 5.0. In this case we want to
    display CHAR fields as CHAR and not as VARCHAR.
    We do it this way as we want to keep the old frm version to enable
    MySQL 4.1 to read these files.
  */
  if (share->frm_version == FRM_VER_TRUE_VARCHAR -1 && frm_image[33] == 5)
    share->frm_version= FRM_VER_TRUE_VARCHAR;

  new_field_pack_flag= frm_image[27];
  new_frm_ver= (frm_image[2] - FRM_VER);
  field_pack_length= new_frm_ver < 2 ? 11 : 17;

  /* Length of the MariaDB extra2 segment in the form file. */
  len = uint2korr(frm_image+4);
  extra2= frm_image + 64;

  if (*extra2 != '/')   // old frm had '/' there
  {
    const uchar *e2end= extra2 + len;
    while (extra2 + 3 < e2end)
    {
      uchar type= *extra2++;
      size_t length= *extra2++;
      if (!length)
      {
        if (extra2 + 2 >= e2end)
          goto err;
        length= uint2korr(extra2);
        extra2+= 2;
        if (length < 256)
          goto err;
      }
      if (extra2 + length > e2end)
        goto err;
      switch (type) {
      case EXTRA2_TABLEDEF_VERSION:
        if (tabledef_version.str) // see init_from_sql_statement_string()
        {
          if (length != tabledef_version.length ||
              memcmp(extra2, tabledef_version.str, length))
            goto err;
        }
        else
        {
          tabledef_version.length= length;
          tabledef_version.str= (uchar*)memdup_root(&mem_root, extra2, length);
          if (!tabledef_version.str)
            goto err;
        }
        break;
      case EXTRA2_ENGINE_TABLEOPTS:
        if (options)
          goto err;
        /* remember but delay parsing until we have read fields and keys */
        options= extra2;
        options_len= length;
        break;
      case EXTRA2_DEFAULT_PART_ENGINE:
#ifdef WITH_PARTITION_STORAGE_ENGINE
        {
          LEX_STRING name= { (char*)extra2, length };
          share->default_part_plugin= ha_resolve_by_name(NULL, &name, false);
          if (!share->default_part_plugin)
            goto err;
        }
#endif
        break;
      case EXTRA2_GIS:
#ifdef HAVE_SPATIAL
        {
          if (gis_options)
            goto err;
          gis_options= extra2;
          gis_options_len= length;
        }
#endif /*HAVE_SPATIAL*/
        break;
      default:
        /* abort frm parsing if it's an unknown but important extra2 value */
        if (type >= EXTRA2_ENGINE_IMPORTANT)
          goto err;
      }
      extra2+= length;
    }
    if (extra2 != e2end)
      goto err;
  }

  if (frm_length < FRM_HEADER_SIZE + len ||
      !(pos= uint4korr(frm_image + FRM_HEADER_SIZE + len)))
    goto err;

  forminfo= frm_image + pos;
  if (forminfo + FRM_FORMINFO_SIZE >= frm_image_end)
    goto err;

#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (frm_image[61] && !share->default_part_plugin)
  {
    enum legacy_db_type db_type= (enum legacy_db_type) (uint) frm_image[61];
    share->default_part_plugin= ha_lock_engine(NULL, ha_checktype(thd, db_type));
    if (!share->default_part_plugin)
      goto err;
  }
#endif
  legacy_db_type= (enum legacy_db_type) (uint) frm_image[3];
  /*
    if the storage engine is dynamic, no point in resolving it by its
    dynamically allocated legacy_db_type. We will resolve it later by name.
  */
  if (legacy_db_type > DB_TYPE_UNKNOWN && 
      legacy_db_type < DB_TYPE_FIRST_DYNAMIC)
    se_plugin= ha_lock_engine(NULL, ha_checktype(thd, legacy_db_type));
  share->db_create_options= db_create_options= uint2korr(frm_image+30);
  share->db_options_in_use= share->db_create_options;
  share->mysql_version= uint4korr(frm_image+51);
  share->null_field_first= 0;
  if (!frm_image[32])				// New frm file in 3.23
  {
    uint cs_org= (((uint) frm_image[41]) << 8) + (uint) frm_image[38];
    uint cs_new= upgrade_collation(share->mysql_version, cs_org);
    if (cs_org != cs_new)
      share->incompatible_version|= HA_CREATE_USED_CHARSET;

    share->avg_row_length= uint4korr(frm_image+34);
    share->transactional= (ha_choice)
      enum_value_with_check(thd, share, "transactional", frm_image[39] & 3, HA_CHOICE_MAX);
    share->page_checksum= (ha_choice)
      enum_value_with_check(thd, share, "page_checksum", (frm_image[39] >> 2) & 3, HA_CHOICE_MAX);
    share->row_type= (enum row_type)
      enum_value_with_check(thd, share, "row_format", frm_image[40], ROW_TYPE_MAX);

    if (cs_new && !(share->table_charset= get_charset(cs_new, MYF(MY_WME))))
      goto err;
    share->null_field_first= 1;
    share->stats_sample_pages= uint2korr(frm_image+42);
    share->stats_auto_recalc= (enum_stats_auto_recalc)(frm_image[44]);
    share->table_check_constraints= uint2korr(frm_image+45);
  }
  if (!share->table_charset)
  {
    const CHARSET_INFO *cs= thd->variables.collation_database;
    /* unknown charset in frm_image[38] or pre-3.23 frm */
    if (use_mb(cs))
    {
      /* Warn that we may be changing the size of character columns */
      sql_print_warning("'%s' had no or invalid character set, "
                        "and default character set is multi-byte, "
                        "so character column sizes may have changed",
                        share->path.str);
    }
    share->table_charset= cs;
  }

  share->db_record_offset= 1;
  share->max_rows= uint4korr(frm_image+18);
  share->min_rows= uint4korr(frm_image+22);

  /* Read keyinformation */
  disk_buff= frm_image + uint2korr(frm_image+6);

  if (disk_buff + 6 >= frm_image_end)
    goto err;

  if (disk_buff[0] & 0x80)
  {
    keys=      (disk_buff[1] << 7) | (disk_buff[0] & 0x7f);
    share->key_parts= key_parts= uint2korr(disk_buff+2);
  }
  else
  {
    keys=      disk_buff[0];
    share->key_parts= key_parts= disk_buff[1];
  }
  share->keys_for_keyread.init(0);
  share->keys_in_use.init(keys);
  ext_key_parts= key_parts;

  len= (uint) uint2korr(disk_buff+4);

  share->reclength = uint2korr(frm_image+16);
  share->stored_rec_length= share->reclength;
  if (frm_image[26] == 1)
    share->system= 1;				/* one-record-database */

  record_offset= (ulong) (uint2korr(frm_image+6)+
                          ((uint2korr(frm_image+14) == 0xffff ?
                            uint4korr(frm_image+47) : uint2korr(frm_image+14))));

  if (record_offset + share->reclength >= frm_length)
    goto err;
 
  if ((n_length= uint4korr(frm_image+55)))
  {
    /* Read extra data segment */
    const uchar *next_chunk, *buff_end;
    DBUG_PRINT("info", ("extra segment size is %u bytes", n_length));
    next_chunk= frm_image + record_offset + share->reclength;
    buff_end= next_chunk + n_length;

    if (buff_end >= frm_image_end)
      goto err;

    share->connect_string.length= uint2korr(next_chunk);
    if (!(share->connect_string.str= strmake_root(&share->mem_root,
                                                  (char*) next_chunk + 2,
                                                  share->connect_string.
                                                  length)))
    {
      goto err;
    }
    next_chunk+= share->connect_string.length + 2;
    if (next_chunk + 2 < buff_end)
    {
      uint str_db_type_length= uint2korr(next_chunk);
      LEX_STRING name;
      name.str= (char*) next_chunk + 2;
      name.length= str_db_type_length;

      plugin_ref tmp_plugin= ha_resolve_by_name(thd, &name, false);
      if (tmp_plugin != NULL && !plugin_equals(tmp_plugin, se_plugin))
      {
        if (se_plugin)
        {
          /* bad file, legacy_db_type did not match the name */
          sql_print_warning("%s.frm is inconsistent: engine typecode %d, engine name %s (%d)",
                        share->normalized_path.str, legacy_db_type,
                        plugin_name(tmp_plugin)->str,
                        ha_legacy_type(plugin_data(tmp_plugin, handlerton *)));
        }
        /*
          tmp_plugin is locked with a local lock.
          we unlock the old value of se_plugin before
          replacing it with a globally locked version of tmp_plugin
        */
        plugin_unlock(NULL, se_plugin);
        se_plugin= plugin_lock(NULL, tmp_plugin);
      }
#ifdef WITH_PARTITION_STORAGE_ENGINE
      else if (str_db_type_length == 9 &&
               !strncmp((char *) next_chunk + 2, "partition", 9))
      {
        /*
          Use partition handler
          tmp_plugin is locked with a local lock.
          we unlock the old value of se_plugin before
          replacing it with a globally locked version of tmp_plugin
        */
        /* Check if the partitioning engine is ready */
        if (!plugin_is_ready(&name, MYSQL_STORAGE_ENGINE_PLUGIN))
        {
          my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0),
                   "--skip-partition");
          goto err;
        }
        plugin_unlock(NULL, se_plugin);
        se_plugin= ha_lock_engine(NULL, partition_hton);
      }
#endif
      else if (!tmp_plugin)
      {
        /* purecov: begin inspected */
        name.str[name.length]=0;
        my_error(ER_UNKNOWN_STORAGE_ENGINE, MYF(0), name.str);
        goto err;
        /* purecov: end */
      }
      next_chunk+= str_db_type_length + 2;
    }

    share->set_use_ext_keys_flag(plugin_hton(se_plugin)->flags & HTON_SUPPORTS_EXTENDED_KEYS);

    if (create_key_infos(disk_buff + 6, frm_image_end, keys, keyinfo,
                         new_frm_ver, ext_key_parts,
                         share, len, &first_keyinfo, &keynames))
      goto err;

    if (next_chunk + 5 < buff_end)
    {
      uint32 partition_info_str_len = uint4korr(next_chunk);
#ifdef WITH_PARTITION_STORAGE_ENGINE
      if ((share->partition_info_buffer_size=
             share->partition_info_str_len= partition_info_str_len))
      {
        if (!(share->partition_info_str= (char*)
              memdup_root(&share->mem_root, next_chunk + 4,
                          partition_info_str_len + 1)))
        {
          goto err;
        }
      }
#else
      if (partition_info_str_len)
      {
        DBUG_PRINT("info", ("WITH_PARTITION_STORAGE_ENGINE is not defined"));
        goto err;
      }
#endif
      next_chunk+= 5 + partition_info_str_len;
    }
    if (share->mysql_version >= 50110 && next_chunk < buff_end)
    {
      /* New auto_partitioned indicator introduced in 5.1.11 */
#ifdef WITH_PARTITION_STORAGE_ENGINE
      share->auto_partitioned= *next_chunk;
#endif
      next_chunk++;
    }
    keyinfo= share->key_info;
    for (i= 0; i < keys; i++, keyinfo++)
    {
      if (keyinfo->flags & HA_USES_PARSER)
      {
        LEX_STRING parser_name;
        if (next_chunk >= buff_end)
        {
          DBUG_PRINT("error",
                     ("fulltext key uses parser that is not defined in .frm"));
          goto err;
        }
        parser_name.str= (char*) next_chunk;
        parser_name.length= strlen((char*) next_chunk);
        next_chunk+= parser_name.length + 1;
        keyinfo->parser= my_plugin_lock_by_name(NULL, &parser_name,
                                                MYSQL_FTPARSER_PLUGIN);
        if (! keyinfo->parser)
        {
          my_error(ER_PLUGIN_IS_NOT_LOADED, MYF(0), parser_name.str);
          goto err;
        }
      }
    }

    if (forminfo[46] == (uchar)255)
    {
      //reading long table comment
      if (next_chunk + 2 > buff_end)
      {
          DBUG_PRINT("error",
                     ("long table comment is not defined in .frm"));
          goto err;
      }
      share->comment.length = uint2korr(next_chunk);
      if (! (share->comment.str= strmake_root(&share->mem_root,
             (char*)next_chunk + 2, share->comment.length)))
      {
          goto err;
      }
      next_chunk+= 2 + share->comment.length;
    }

    DBUG_ASSERT(next_chunk <= buff_end);

    if (share->db_create_options & HA_OPTION_TEXT_CREATE_OPTIONS_legacy)
    {
      if (options)
        goto err;
      options_len= uint4korr(next_chunk);
      options= next_chunk + 4;
      next_chunk+= options_len + 4;
    }
    DBUG_ASSERT(next_chunk <= buff_end);
  }
  else
  {
    if (create_key_infos(disk_buff + 6, frm_image_end, keys, keyinfo,
                         new_frm_ver, ext_key_parts,
                         share, len, &first_keyinfo, &keynames))
      goto err;
  }

  share->key_block_size= uint2korr(frm_image+62);

  if (share->db_plugin && !plugin_equals(share->db_plugin, se_plugin))
    goto err; // wrong engine (someone changed the frm under our feet?)

  rec_buff_length= ALIGN_SIZE(share->reclength + 1);
  share->rec_buff_length= rec_buff_length;
  if (!(record= (uchar *) alloc_root(&share->mem_root, rec_buff_length)))
    goto err;                          /* purecov: inspected */
  MEM_NOACCESS(record, rec_buff_length);
  MEM_UNDEFINED(record, share->reclength);
  share->default_values= record;
  memcpy(record, frm_image + record_offset, share->reclength);

  disk_buff= frm_image + pos + FRM_FORMINFO_SIZE;

  share->fields= uint2korr(forminfo+258);
  pos= uint2korr(forminfo+260);   /* Length of all screens */
  n_length= uint2korr(forminfo+268);
  interval_count= uint2korr(forminfo+270);
  interval_parts= uint2korr(forminfo+272);
  int_length= uint2korr(forminfo+274);
  share->null_fields= uint2korr(forminfo+282);
  com_length= uint2korr(forminfo+284);
  vcol_screen_length= uint2korr(forminfo+286);
  share->virtual_fields= share->default_expressions=
    share->field_check_constraints= share->default_fields= 0;
  share->stored_fields= share->fields;
  if (forminfo[46] != (uchar)255)
  {
    share->comment.length=  (int) (forminfo[46]);
    share->comment.str= strmake_root(&share->mem_root, (char*) forminfo+47,
                                     share->comment.length);
  }

  DBUG_PRINT("info",("i_count: %d  i_parts: %d  index: %d  n_length: %d  int_length: %d  com_length: %d  vcol_screen_length: %d", interval_count,interval_parts, keys,n_length,int_length, com_length, vcol_screen_length));

  /*
    We load the following things into TYPELIBs:
    - One TYPELIB for field names
    - interval_count TYPELIBs for ENUM/SET values
    - One TYPELIB for key names
    Every TYPELIB requires one extra value with a NULL pointer and zero length,
    which is the end-of-values marker.
    TODO-10.5+:
    Note, we should eventually reuse this total_typelib_value_count
    to allocate interval_array. The below code reserves less space
    than total_typelib_value_count pointers. So it seems `interval_array`
    and `names` overlap in the memory. Too dangerous to fix in 10.1.
  */
  total_typelib_value_count=
    (share->fields  +              1/*end-of-values marker*/) +
    (interval_parts + interval_count/*end-of-values markers*/) +
    (keys           +              1/*end-of-values marker*/);

  if (!multi_alloc_root(&share->mem_root,
                        &share->field, (uint)(share->fields+1)*sizeof(Field*),
                        &share->intervals, (uint)interval_count*sizeof(TYPELIB),
                        &share->check_constraints, (uint) share->table_check_constraints * sizeof(Virtual_column_info*),
                        /*
                           This looks wrong: shouldn't it be (+2+interval_count)
                           instread of (+3) ?
                        */
                        &interval_array, (uint) (share->fields+interval_parts+ keys+3)*sizeof(char *),
                        &typelib_value_lengths, total_typelib_value_count * sizeof(uint *),
                        &names, (uint) (n_length+int_length),
                        &comment_pos, (uint) com_length,
                        &vcol_screen_pos, vcol_screen_length,
                        NullS))

    goto err;

  field_ptr= share->field;
  table_check_constraints= share->check_constraints;
  read_length=(uint) (share->fields * field_pack_length +
		      pos+ (uint) (n_length+int_length+com_length+
		                   vcol_screen_length));
  strpos= disk_buff+pos;

  if (!interval_count)
    share->intervals= 0;			// For better debugging

  share->vcol_defs.str= vcol_screen_pos;
  share->vcol_defs.length= vcol_screen_length;

  memcpy(names, strpos+(share->fields*field_pack_length), n_length+int_length);
  memcpy(comment_pos, disk_buff+read_length-com_length-vcol_screen_length, 
         com_length);
  memcpy(vcol_screen_pos, disk_buff+read_length-vcol_screen_length, 
         vcol_screen_length);

  if (fix_type_pointers(&interval_array, &typelib_value_lengths,
                        &share->fieldnames, 1, names, n_length) ||
      share->fieldnames.count != share->fields)
    goto err;

  if (fix_type_pointers(&interval_array, &typelib_value_lengths,
                        share->intervals, interval_count,
                        names + n_length, int_length))
    goto err;

  if (keynames.length &&
      (fix_type_pointers(&interval_array, &typelib_value_lengths,
                         &share->keynames, 1, keynames.str, keynames.length) ||
      share->keynames.count != keys))
    goto err;

 /* Allocate handler */
  if (!(handler_file= get_new_handler(share, thd->mem_root,
                                      plugin_hton(se_plugin))))
    goto err;

  if (handler_file->set_ha_share_ref(&share->ha_share))
    goto err;

  record= share->default_values-1;              /* Fieldstart = 1 */
  null_bits_are_used= share->null_fields != 0;
  if (share->null_field_first)
  {
    null_flags= null_pos= record+1;
    null_bit_pos= (db_create_options & HA_OPTION_PACK_RECORD) ? 0 : 1;
    /*
      null_bytes below is only correct under the condition that
      there are no bit fields.  Correct values is set below after the
      table struct is initialized
    */
    share->null_bytes= (share->null_fields + null_bit_pos + 7) / 8;
  }
#ifndef WE_WANT_TO_SUPPORT_VERY_OLD_FRM_FILES
  else
  {
    share->null_bytes= (share->null_fields+7)/8;
    null_flags= null_pos= record + 1 + share->reclength - share->null_bytes;
    null_bit_pos= 0;
  }
#endif

  use_hash= share->fields >= MAX_FIELDS_BEFORE_HASH;
  if (use_hash)
    use_hash= !my_hash_init(&share->name_hash,
                            system_charset_info,
                            share->fields,0,0,
                            (my_hash_get_key) get_field_name,0,0);

  if (share->mysql_version >= 50700 && share->mysql_version < 100000 &&
      vcol_screen_length)
  {
    /*
      MySQL 5.7 stores the null bits for not stored fields last.
      Calculate the position for them.
    */
    mysql57_null_bits= 1;
    mysql57_vcol_null_pos= null_pos;
    mysql57_vcol_null_bit_pos= null_bit_pos;
    mysql57_calculate_null_position(share, &mysql57_vcol_null_pos,
                                    &mysql57_vcol_null_bit_pos,
                                    strpos, vcol_screen_pos);
  }

  for (i=0 ; i < share->fields; i++, strpos+=field_pack_length, field_ptr++)
  {
    uint pack_flag, interval_nr, unireg_type, recpos, field_length;
    uint vcol_info_length=0;
    uint vcol_expr_length=0;
    enum_field_types field_type;
    CHARSET_INFO *charset=NULL;
    Field::geometry_type geom_type= Field::GEOM_GEOMETRY;
    LEX_STRING comment;
    Virtual_column_info *vcol_info= 0;
    uint gis_length, gis_decimals, srid= 0;
    Field::utype unireg_check;

    if (new_frm_ver >= 3)
    {
      /* new frm file in 4.1 */
      field_length= uint2korr(strpos+3);
      recpos=	    uint3korr(strpos+5);
      pack_flag=    uint2korr(strpos+8);
      unireg_type=  (uint) strpos[10];
      interval_nr=  (uint) strpos[12];
      uint comment_length=uint2korr(strpos+15);
      field_type=(enum_field_types) (uint) strpos[13];

      /* charset and geometry_type share the same byte in frm */
      if (field_type == MYSQL_TYPE_GEOMETRY)
      {
#ifdef HAVE_SPATIAL
        uint gis_opt_read;
        Field_geom::storage_type st_type;
	geom_type= (Field::geometry_type) strpos[14];
	charset= &my_charset_bin;
        gis_opt_read= gis_field_options_read(gis_options, gis_options_len,
            &st_type, &gis_length, &gis_decimals, &srid);
        gis_options+= gis_opt_read;
        gis_options_len-= gis_opt_read;
#else
	goto err;
#endif
      }
      else
      {
        uint cs_org= strpos[14] + (((uint) strpos[11]) << 8);
        uint cs_new= upgrade_collation(share->mysql_version, cs_org);
        if (cs_org != cs_new)
          share->incompatible_version|= HA_CREATE_USED_CHARSET;
        if (!cs_new)
          charset= &my_charset_bin;
        else if (!(charset= get_charset(cs_new, MYF(0))))
        {
          const char *csname= get_charset_name((uint) cs_new);
          char tmp[10];
          if (!csname || csname[0] =='?')
          {
            my_snprintf(tmp, sizeof(tmp), "#%d", cs_new);
            csname= tmp;
          }
          my_printf_error(ER_UNKNOWN_COLLATION,
                          "Unknown collation '%s' in table '%-.64s' definition", 
                          MYF(0), csname, share->table_name.str);
          goto err;
        }
      }

      if ((uchar)field_type == (uchar)MYSQL_TYPE_VIRTUAL)
      {
        if (!interval_nr) // Expect non-null expression
          goto err;
        /*
          MariaDB version 10.0 version.
          The interval_id byte in the .frm file stores the length of the
          expression statement for a virtual column.
        */
        vcol_info_length= interval_nr;
        interval_nr= 0;
      }

      if (!comment_length)
      {
	comment.str= (char*) "";
	comment.length=0;
      }
      else
      {
	comment.str=    (char*) comment_pos;
	comment.length= comment_length;
	comment_pos+=   comment_length;
      }

      if (unireg_type & MYSQL57_GENERATED_FIELD)
      {
        unireg_type&= MYSQL57_GENERATED_FIELD;

        /*
          MySQL 5.7 generated fields

          byte 1        = 1
          byte 2,3      = expr length
          byte 4        = stored_in_db
          byte 5..      = expr
        */
        if ((uint)(vcol_screen_pos)[0] != 1)
          goto err;
        vcol_info= new (&share->mem_root) Virtual_column_info();
        vcol_info_length= uint2korr(vcol_screen_pos + 1);
        if (!vcol_info_length) // Expect non-empty expression
          goto err;
        vcol_info->stored_in_db= vcol_screen_pos[3];
        vcol_info->utf8= 0;
        vcol_screen_pos+= vcol_info_length + MYSQL57_GCOL_HEADER_SIZE;;
        share->virtual_fields++;
        vcol_info_length= 0;
      }

      if (vcol_info_length)
      {
        /*
          Old virtual field information before 10.2

          Get virtual column data stored in the .frm file as follows:
          byte 1      = 1 | 2
          byte 2      = sql_type
          byte 3      = flags. 1 for stored_in_db
          [byte 4]    = optional interval_id for sql_type (if byte 1 == 2)
          next byte ...  = virtual column expression (text data)
        */

        vcol_info= new (&share->mem_root) Virtual_column_info();
        bool opt_interval_id= (uint)vcol_screen_pos[0] == 2;
        field_type= (enum_field_types) (uchar) vcol_screen_pos[1];
        if (opt_interval_id)
          interval_nr= (uint)vcol_screen_pos[3];
        else if ((uint)vcol_screen_pos[0] != 1)
          goto err;
        bool stored= vcol_screen_pos[2] & 1;
        vcol_info->stored_in_db= stored;
        vcol_info->set_vcol_type(stored ? VCOL_GENERATED_STORED : VCOL_GENERATED_VIRTUAL);
        vcol_expr_length= vcol_info_length -
                          (uint)(FRM_VCOL_OLD_HEADER_SIZE(opt_interval_id));
        vcol_info->utf8= 0; // before 10.2.1 the charset was unknown
        int2store(vcol_screen_pos+1, vcol_expr_length); // for parse_vcol_defs()
        vcol_screen_pos+= vcol_info_length;
        share->virtual_fields++;
      }
    }
    else
    {
      field_length= (uint) strpos[3];
      recpos=	    uint2korr(strpos+4),
      pack_flag=    uint2korr(strpos+6);
      pack_flag&=   ~FIELDFLAG_NO_DEFAULT;     // Safety for old files
      unireg_type=  (uint) strpos[8];
      interval_nr=  (uint) strpos[10];

      /* old frm file */
      field_type= (enum_field_types) f_packtype(pack_flag);
      if (f_is_binary(pack_flag))
      {
        /*
          Try to choose the best 4.1 type:
          - for 4.0 "CHAR(N) BINARY" or "VARCHAR(N) BINARY" 
           try to find a binary collation for character set.
          - for other types (e.g. BLOB) just use my_charset_bin. 
        */
        if (!f_is_blob(pack_flag))
        {
          // 3.23 or 4.0 string
          if (!(charset= get_charset_by_csname(share->table_charset->csname,
                                               MY_CS_BINSORT, MYF(0))))
            charset= &my_charset_bin;
        }
        else
          charset= &my_charset_bin;
      }
      else
        charset= share->table_charset;
      bzero((char*) &comment, sizeof(comment));
    }

    /* Remove >32 decimals from old files */
    if (share->mysql_version < 100200)
      pack_flag&= ~FIELDFLAG_LONG_DECIMAL;

    if (interval_nr && charset->mbminlen > 1)
    {
      /* Unescape UCS2 intervals from HEX notation */
      TYPELIB *interval= share->intervals + interval_nr - 1;
      unhex_type2(interval);
    }

#ifndef TO_BE_DELETED_ON_PRODUCTION
    if (field_type == MYSQL_TYPE_NEWDECIMAL && !share->mysql_version)
    {
      /*
        Fix pack length of old decimal values from 5.0.3 -> 5.0.4
        The difference is that in the old version we stored precision
        in the .frm table while we now store the display_length
      */
      uint decimals= f_decimals(pack_flag);
      field_length= my_decimal_precision_to_length(field_length,
                                                   decimals,
                                                   f_is_dec(pack_flag) == 0);
      sql_print_error("Found incompatible DECIMAL field '%s' in %s; "
                      "Please do \"ALTER TABLE '%s' FORCE\" to fix it!",
                      share->fieldnames.type_names[i], share->table_name.str,
                      share->table_name.str);
      push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_CRASHED_ON_USAGE,
                          "Found incompatible DECIMAL field '%s' in %s; "
                          "Please do \"ALTER TABLE '%s' FORCE\" to fix it!",
                          share->fieldnames.type_names[i],
                          share->table_name.str,
                          share->table_name.str);
      share->crashed= 1;                        // Marker for CHECK TABLE
    }
#endif

    if (mysql57_null_bits && vcol_info && !vcol_info->stored_in_db)
    {
      swap_variables(uchar*, null_pos, mysql57_vcol_null_pos);
      swap_variables(uint, null_bit_pos, mysql57_vcol_null_bit_pos);
    }

    /* Convert pre-10.2.2 timestamps to use Field::default_value */
    unireg_check= (Field::utype) MTYP_TYPENR(unireg_type);
    *field_ptr= reg_field=
      make_field(share, &share->mem_root, record+recpos, (uint32) field_length,
		 null_pos, null_bit_pos, pack_flag, field_type, charset,
		 geom_type, srid, unireg_check,
		 (interval_nr ? share->intervals+interval_nr-1 : NULL),
		 share->fieldnames.type_names[i]);
    if (!reg_field)				// Not supported field type
      goto err;

    if (unireg_check == Field::TIMESTAMP_DNUN_FIELD ||
        unireg_check == Field::TIMESTAMP_DN_FIELD)
    {
      reg_field->default_value= new (&share->mem_root) Virtual_column_info();
      reg_field->default_value->set_vcol_type(VCOL_DEFAULT);
      reg_field->default_value->stored_in_db= 1;
      share->default_expressions++;
    }

    reg_field->field_index= i;
    reg_field->comment=comment;
    reg_field->vcol_info= vcol_info;
    if (field_type == MYSQL_TYPE_BIT && !f_bit_as_char(pack_flag))
    {
      null_bits_are_used= 1;
      if ((null_bit_pos+= field_length & 7) > 7)
      {
        null_pos++;
        null_bit_pos-= 8;
      }
    }
    if (!(reg_field->flags & NOT_NULL_FLAG))
    {
      if (!(null_bit_pos= (null_bit_pos + 1) & 7))
        null_pos++;
    }

    if (vcol_info)
    {
      vcol_info->name.str= const_cast<char*>(reg_field->field_name);
      vcol_info->name.length = strlen(reg_field->field_name);
      if (mysql57_null_bits && !vcol_info->stored_in_db)
      {
        /* MySQL 5.7 has null bits last */
        swap_variables(uchar*, null_pos, mysql57_vcol_null_pos);
        swap_variables(uint, null_bit_pos, mysql57_vcol_null_bit_pos);
      }
    }

    if (f_no_default(pack_flag))
      reg_field->flags|= NO_DEFAULT_VALUE_FLAG;

    if (reg_field->unireg_check == Field::NEXT_NUMBER)
      share->found_next_number_field= field_ptr;

    if (use_hash && my_hash_insert(&share->name_hash, (uchar*) field_ptr))
      goto err;
    if (!reg_field->stored_in_db())
    {
      share->stored_fields--;
      if (share->stored_rec_length>=recpos)
        share->stored_rec_length= recpos-1;
    }
    if (reg_field->has_update_default_function())
    {
      has_update_default_function= 1;
      if (!reg_field->default_value)
        share->default_fields++;
    }
  }
  *field_ptr=0;					// End marker
  /* Sanity checks: */
  DBUG_ASSERT(share->fields>=share->stored_fields);
  DBUG_ASSERT(share->reclength>=share->stored_rec_length);

  if (mysql57_null_bits)
  {
    /* We want to store the value for the last bits */
    swap_variables(uchar*, null_pos, mysql57_vcol_null_pos);
    swap_variables(uint, null_bit_pos, mysql57_vcol_null_bit_pos);
    DBUG_ASSERT((null_pos + (null_bit_pos + 7) / 8) <= share->field[0]->ptr);
  }

  /* Fix key->name and key_part->field */
  if (key_parts)
  {
    uint add_first_key_parts= 0;
    longlong ha_option= handler_file->ha_table_flags();
    keyinfo= share->key_info;
    uint primary_key= my_strcasecmp(system_charset_info, share->keynames.type_names[0],
                                    primary_key_name) ? MAX_KEY : 0;
    KEY* key_first_info= NULL;

    if (primary_key >= MAX_KEY && keyinfo->flags & HA_NOSAME)
    {
      /*
        If the UNIQUE key doesn't have NULL columns and is not a part key
        declare this as a primary key.
      */
      primary_key= 0;
      key_part= keyinfo->key_part;
      for (i=0 ; i < keyinfo->user_defined_key_parts ;i++)
      {
        DBUG_ASSERT(key_part[i].fieldnr > 0);
        // Table field corresponding to the i'th key part.
        Field *table_field= share->field[key_part[i].fieldnr - 1];

        /*
          If the key column is of NOT NULL BLOB type, then it
          will definitly have key prefix. And if key part prefix size
          is equal to the BLOB column max size, then we can promote
          it to primary key.
        */
        if (!table_field->real_maybe_null() &&
            table_field->type() == MYSQL_TYPE_BLOB &&
            table_field->field_length == key_part[i].length)
          continue;

        if (table_field->real_maybe_null() ||
            table_field->key_length() != key_part[i].length)
        {
          primary_key= MAX_KEY;		// Can't be used
          break;
        }
      }
    }

    if (share->use_ext_keys)
    { 
      if (primary_key >= MAX_KEY)
      {
        add_first_key_parts= 0;
        share->set_use_ext_keys_flag(FALSE);
      }
      else
      {
        add_first_key_parts= first_keyinfo.user_defined_key_parts;
        /* 
          Do not add components of the primary key starting from
          the major component defined over the beginning of a field.
	*/
	for (i= 0; i < first_keyinfo.user_defined_key_parts; i++)
	{
          uint fieldnr= keyinfo[0].key_part[i].fieldnr;
          if (share->field[fieldnr-1]->key_length() !=
              keyinfo[0].key_part[i].length)
	  {
            add_first_key_parts= i;
            break;
          }
        }
      }   
    }

    key_first_info= keyinfo;
    for (uint key=0 ; key < keys ; key++,keyinfo++)
    {
      uint usable_parts= 0;
      keyinfo->name=(char*) share->keynames.type_names[key];
      keyinfo->name_length= strlen(keyinfo->name);
      keyinfo->cache_name=
        (uchar*) alloc_root(&share->mem_root,
                            share->table_cache_key.length+
                            keyinfo->name_length + 1);
      if (keyinfo->cache_name)           // If not out of memory
      {
        uchar *pos= keyinfo->cache_name;
        memcpy(pos, share->table_cache_key.str, share->table_cache_key.length);
        memcpy(pos + share->table_cache_key.length, keyinfo->name,
               keyinfo->name_length+1);
      }

      if (ext_key_parts > share->key_parts && key)
      {
        KEY_PART_INFO *new_key_part= (keyinfo-1)->key_part +
                                     (keyinfo-1)->ext_key_parts;
        uint add_keyparts_for_this_key= add_first_key_parts;
        uint length_bytes= 0, len_null_byte= 0, ext_key_length= 0;
        Field *field;

        /* 
          Do not extend the key that contains a component
          defined over the beginning of a field.
	*/ 
        for (i= 0; i < keyinfo->user_defined_key_parts; i++)
        {
          uint fieldnr= keyinfo->key_part[i].fieldnr;
          field= share->field[keyinfo->key_part[i].fieldnr-1];

          if (field->null_ptr)
            len_null_byte= HA_KEY_NULL_LENGTH;

          if (field->type() == MYSQL_TYPE_BLOB ||
             field->real_type() == MYSQL_TYPE_VARCHAR ||
             field->type() == MYSQL_TYPE_GEOMETRY)
          {
            length_bytes= HA_KEY_BLOB_LENGTH;
          }

          ext_key_length+= keyinfo->key_part[i].length + len_null_byte
                            + length_bytes;
          if (share->field[fieldnr-1]->key_length() !=
              keyinfo->key_part[i].length)
	  {
            add_keyparts_for_this_key= 0;
            break;
          }
        }

        if (add_keyparts_for_this_key)
        {
          for (i= 0; i < add_keyparts_for_this_key; i++)
          {
            uint pk_part_length= key_first_info->key_part[i].store_length;
            if (keyinfo->ext_key_part_map & 1<<i)
            {
              if (ext_key_length + pk_part_length > MAX_DATA_LENGTH_FOR_KEY)
              {
                add_keyparts_for_this_key= i;
                break;
              }
              ext_key_length+= pk_part_length;
            }
          }
        }

        if (add_keyparts_for_this_key < keyinfo->ext_key_parts -
                                        keyinfo->user_defined_key_parts)
        {
          share->ext_key_parts-= keyinfo->ext_key_parts;
          key_part_map ext_key_part_map= keyinfo->ext_key_part_map;
          keyinfo->ext_key_parts= keyinfo->user_defined_key_parts;
          keyinfo->ext_key_flags= keyinfo->flags;
	  keyinfo->ext_key_part_map= 0; 
          for (i= 0; i < add_keyparts_for_this_key; i++)
	  {
            if (ext_key_part_map & 1<<i)
	    {
              keyinfo->ext_key_part_map|= 1<<i;
	      keyinfo->ext_key_parts++;
            }
          }
          share->ext_key_parts+= keyinfo->ext_key_parts;
        }
        if (new_key_part != keyinfo->key_part)
	{
          memmove(new_key_part, keyinfo->key_part,
                  sizeof(KEY_PART_INFO) * keyinfo->ext_key_parts);
          keyinfo->key_part= new_key_part;
        }
      }
 
      /* Fix fulltext keys for old .frm files */
      if (share->key_info[key].flags & HA_FULLTEXT)
	share->key_info[key].algorithm= HA_KEY_ALG_FULLTEXT;

      key_part= keyinfo->key_part;
      uint key_parts= share->use_ext_keys ? keyinfo->ext_key_parts :
	                                    keyinfo->user_defined_key_parts;
      for (i=0; i < key_parts; key_part++, i++)
      {
        Field *field;
	if (new_field_pack_flag <= 1)
	  key_part->fieldnr= (uint16) find_field(share->field,
                                                 share->default_values,
                                                 (uint) key_part->offset,
                                                 (uint) key_part->length);
	if (!key_part->fieldnr)
          goto err;

        field= key_part->field= share->field[key_part->fieldnr-1];
        key_part->type= field->key_type();
        if (field->null_ptr)
        {
          key_part->null_offset=(uint) ((uchar*) field->null_ptr -
                                        share->default_values);
          key_part->null_bit= field->null_bit;
          key_part->store_length+=HA_KEY_NULL_LENGTH;
          keyinfo->flags|=HA_NULL_PART_KEY;
          keyinfo->key_length+= HA_KEY_NULL_LENGTH;
        }
        if (field->type() == MYSQL_TYPE_BLOB ||
            field->real_type() == MYSQL_TYPE_VARCHAR ||
            field->type() == MYSQL_TYPE_GEOMETRY)
        {
          if (field->type() == MYSQL_TYPE_BLOB ||
              field->type() == MYSQL_TYPE_GEOMETRY)
            key_part->key_part_flag|= HA_BLOB_PART;
          else
            key_part->key_part_flag|= HA_VAR_LENGTH_PART;
          key_part->store_length+=HA_KEY_BLOB_LENGTH;
          keyinfo->key_length+= HA_KEY_BLOB_LENGTH;
        }
        if (field->type() == MYSQL_TYPE_BIT)
          key_part->key_part_flag|= HA_BIT_PART;

        if (i == 0 && key != primary_key)
          field->flags |= (((keyinfo->flags & HA_NOSAME) &&
                           (keyinfo->user_defined_key_parts == 1)) ?
                           UNIQUE_KEY_FLAG : MULTIPLE_KEY_FLAG);
        if (i == 0)
          field->key_start.set_bit(key);
        if (field->key_length() == key_part->length &&
            !(field->flags & BLOB_FLAG))
        {
          if (handler_file->index_flags(key, i, 0) & HA_KEYREAD_ONLY)
          {
            share->keys_for_keyread.set_bit(key);
            field->part_of_key.set_bit(key);
            if (i < keyinfo->user_defined_key_parts)
              field->part_of_key_not_clustered.set_bit(key);
          }
          if (handler_file->index_flags(key, i, 1) & HA_READ_ORDER)
            field->part_of_sortkey.set_bit(key);
        }
        if (!(key_part->key_part_flag & HA_REVERSE_SORT) &&
            usable_parts == i)
          usable_parts++;			// For FILESORT
        field->flags|= PART_KEY_FLAG;
        if (key == primary_key)
        {
          field->flags|= PRI_KEY_FLAG;
          /*
            If this field is part of the primary key and all keys contains
            the primary key, then we can use any key to find this column
          */
          if (ha_option & HA_PRIMARY_KEY_IN_READ_INDEX)
          {
            if (field->key_length() == key_part->length &&
                !(field->flags & BLOB_FLAG))
              field->part_of_key= share->keys_in_use;
            if (field->part_of_sortkey.is_set(key))
              field->part_of_sortkey= share->keys_in_use;
          }
        }
        if (field->key_length() != key_part->length)
        {
#ifndef TO_BE_DELETED_ON_PRODUCTION
          if (field->type() == MYSQL_TYPE_NEWDECIMAL)
          {
            /*
              Fix a fatal error in decimal key handling that causes crashes
              on Innodb. We fix it by reducing the key length so that
              InnoDB never gets a too big key when searching.
              This allows the end user to do an ALTER TABLE to fix the
              error.
            */
            keyinfo->key_length-= (key_part->length - field->key_length());
            key_part->store_length-= (uint16)(key_part->length -
                                              field->key_length());
            key_part->length= (uint16)field->key_length();
            sql_print_error("Found wrong key definition in %s; "
                            "Please do \"ALTER TABLE '%s' FORCE \" to fix it!",
                            share->table_name.str,
                            share->table_name.str);
            push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                                ER_CRASHED_ON_USAGE,
                                "Found wrong key definition in %s; "
                                "Please do \"ALTER TABLE '%s' FORCE\" to fix "
                                "it!",
                                share->table_name.str,
                                share->table_name.str);
            share->crashed= 1;                // Marker for CHECK TABLE
            continue;
          }
#endif
          key_part->key_part_flag|= HA_PART_KEY_SEG;
        }
        if (field->real_maybe_null())
          key_part->key_part_flag|= HA_NULL_PART;
        /*
          Sometimes we can compare key parts for equality with memcmp.
          But not always.
        */
        if (!(key_part->key_part_flag & (HA_BLOB_PART | HA_VAR_LENGTH_PART |
                                         HA_BIT_PART)) &&
            key_part->type != HA_KEYTYPE_FLOAT &&
            key_part->type == HA_KEYTYPE_DOUBLE)
          key_part->key_part_flag|= HA_CAN_MEMCMP;
      }
      keyinfo->usable_key_parts= usable_parts; // Filesort

      set_if_bigger(share->max_key_length,keyinfo->key_length+
                    keyinfo->user_defined_key_parts);
      share->total_key_length+= keyinfo->key_length;
      /*
        MERGE tables do not have unique indexes. But every key could be
        an unique index on the underlying MyISAM table. (Bug #10400)
      */
      if ((keyinfo->flags & HA_NOSAME) ||
          (ha_option & HA_ANY_INDEX_MAY_BE_UNIQUE))
        set_if_bigger(share->max_unique_length,keyinfo->key_length);
    }
    if (primary_key < MAX_KEY &&
	(share->keys_in_use.is_set(primary_key)))
    {
      share->primary_key= primary_key;
      /*
	If we are using an integer as the primary key then allow the user to
	refer to it as '_rowid'
      */
      if (share->key_info[primary_key].user_defined_key_parts == 1)
      {
	Field *field= share->key_info[primary_key].key_part[0].field;
	if (field && field->result_type() == INT_RESULT)
        {
          /* note that fieldnr here (and rowid_field_offset) starts from 1 */
	  share->rowid_field_offset= (share->key_info[primary_key].key_part[0].
                                      fieldnr);
        }
      }
    }
    else
      share->primary_key = MAX_KEY; // we do not have a primary key
  }
  else
    share->primary_key= MAX_KEY;
  if (new_field_pack_flag <= 1)
  {
    /* Old file format with default as not null */
    uint null_length= (share->null_fields+7)/8;
    bfill(share->default_values + (null_flags - (uchar*) record),
          null_length, 255);
  }

  /* Handle virtual expressions */
  if (vcol_screen_length && share->frm_version >= FRM_VER_EXPRESSSIONS)
  {
    uchar *vcol_screen_end= vcol_screen_pos + vcol_screen_length;

    /* Skip header */
    vcol_screen_pos+= FRM_VCOL_NEW_BASE_SIZE;
    share->vcol_defs.str+= FRM_VCOL_NEW_BASE_SIZE;
    share->vcol_defs.length-= FRM_VCOL_NEW_BASE_SIZE;

    /*
      Read virtual columns, default values and check constraints
      See pack_expression() for how data is stored
    */
    while (vcol_screen_pos < vcol_screen_end)
    {
      Virtual_column_info *vcol_info;
      uint type=         (uint) vcol_screen_pos[0];
      uint field_nr=     uint2korr(vcol_screen_pos+1);
      uint expr_length=  uint2korr(vcol_screen_pos+3);
      uint name_length=  (uint) vcol_screen_pos[5];

      if (!(vcol_info=   new (&share->mem_root) Virtual_column_info()))
        goto err;

      /* The following can only be true for check_constraints */

      if (field_nr != UINT_MAX16)
      {
        DBUG_ASSERT(field_nr < share->fields);
        reg_field= share->field[field_nr];
      }
      else
      {
        reg_field= 0;
        DBUG_ASSERT(name_length);
      }

      vcol_screen_pos+= FRM_VCOL_NEW_HEADER_SIZE;
      vcol_info->set_vcol_type((enum_vcol_info_type) type);
      vcol_info->name.length= name_length;
      if (name_length)
        vcol_info->name.str= strmake_root(&share->mem_root,
                                          (char*)vcol_screen_pos, name_length);
      else
      {
        vcol_info->name.str= const_cast<char*>(reg_field->field_name);
        vcol_info->name.length = strlen(reg_field->field_name);
      }
      vcol_screen_pos+= name_length + expr_length;

      switch (type) {
      case VCOL_GENERATED_VIRTUAL:
      {
        uint recpos;
        reg_field->vcol_info= vcol_info;
        share->virtual_fields++;
        share->stored_fields--;
        if (reg_field->flags & BLOB_FLAG)
          share->virtual_not_stored_blob_fields++;
        /* Correct stored_rec_length as non stored fields are last */
        recpos= (uint) (reg_field->ptr - record);
        if (share->stored_rec_length >= recpos)
          share->stored_rec_length= recpos-1;
        break;
      }
      case VCOL_GENERATED_STORED:
        vcol_info->stored_in_db= 1;
        DBUG_ASSERT(!reg_field->vcol_info);
        reg_field->vcol_info= vcol_info;
        share->virtual_fields++;
        break;
      case VCOL_DEFAULT:
        vcol_info->stored_in_db= 1;
        DBUG_ASSERT(!reg_field->default_value);
        reg_field->default_value=    vcol_info;
        share->default_expressions++;
        break;
      case VCOL_CHECK_FIELD:
        DBUG_ASSERT(!reg_field->check_constraint);
        reg_field->check_constraint= vcol_info;
        share->field_check_constraints++;
        break;
      case VCOL_CHECK_TABLE:
        *(table_check_constraints++)= vcol_info;
        break;
      }
    }
  }
  DBUG_ASSERT((uint) (table_check_constraints - share->check_constraints) ==
              (uint) (share->table_check_constraints -
                      share->field_check_constraints));

  if (options)
  {
    DBUG_ASSERT(options_len);
    if (engine_table_options_frm_read(options, options_len, share))
      goto err;
  }
  if (parse_engine_table_options(thd, handler_file->partition_ht(), share))
    goto err;

  if (share->found_next_number_field)
  {
    reg_field= *share->found_next_number_field;
    if ((int) (share->next_number_index= (uint)
	       find_ref_key(share->key_info, keys,
                            share->default_values, reg_field,
			    &share->next_number_key_offset,
                            &share->next_number_keypart)) < 0)
      goto err; // Wrong field definition
    reg_field->flags |= AUTO_INCREMENT_FLAG;
  }

  if (share->blob_fields)
  {
    Field **ptr;
    uint k, *save;

    /* Store offsets to blob fields to find them fast */
    if (!(share->blob_field= save=
	  (uint*) alloc_root(&share->mem_root,
                             (uint) (share->blob_fields* sizeof(uint)))))
      goto err;
    for (k=0, ptr= share->field ; *ptr ; ptr++, k++)
    {
      if ((*ptr)->flags & BLOB_FLAG)
	(*save++)= k;
    }
  }

  /*
    the correct null_bytes can now be set, since bitfields have been taken
    into account
  */
  share->null_bytes= (uint)(null_pos - (uchar*) null_flags +
                      (null_bit_pos + 7) / 8);
  share->last_null_bit_pos= null_bit_pos;
  share->null_bytes_for_compare= null_bits_are_used ? share->null_bytes : 0;
  share->can_cmp_whole_record= (share->blob_fields == 0 &&
                                share->varchar_fields == 0);

  share->column_bitmap_size= bitmap_buffer_size(share->fields);

  bitmap_count= 1;
  if (share->table_check_constraints)
  {
    feature_check_constraint++;
    if (!(share->check_set= (MY_BITMAP*)
          alloc_root(&share->mem_root, sizeof(*share->check_set))))
      goto err;
    bitmap_count++;
  }
  if (!(bitmaps= (my_bitmap_map*) alloc_root(&share->mem_root,
                                             share->column_bitmap_size *
                                             bitmap_count)))
    goto err;
  my_bitmap_init(&share->all_set, bitmaps, share->fields, FALSE);
  bitmap_set_all(&share->all_set);
  if (share->check_set)
  {
    /*
      Bitmap for fields used by CHECK constraint. Will be filled up
      at first usage of table.
    */
    my_bitmap_init(share->check_set,
                   (my_bitmap_map*) ((uchar*) bitmaps +
                                     share->column_bitmap_size),
                   share->fields, FALSE);
    bitmap_clear_all(share->check_set);
  }

  delete handler_file;
#ifndef DBUG_OFF
  if (use_hash)
    (void) my_hash_check(&share->name_hash);
#endif

  share->db_plugin= se_plugin;
  share->error= OPEN_FRM_OK;
  thd->status_var.opened_shares++;
  thd->mem_root= old_root;
  DBUG_RETURN(0);

 err:
  share->error= OPEN_FRM_CORRUPTED;
  share->open_errno= my_errno;
  delete handler_file;
  plugin_unlock(0, se_plugin);
  my_hash_free(&share->name_hash);

  if (!thd->is_error())
    open_table_error(share, OPEN_FRM_CORRUPTED, share->open_errno);

  thd->mem_root= old_root;
  DBUG_RETURN(HA_ERR_NOT_A_TABLE);
}


static bool sql_unusable_for_discovery(THD *thd, handlerton *engine,
                                       const char *sql)
{
  LEX *lex= thd->lex;
  HA_CREATE_INFO *create_info= &lex->create_info;

  // ... not CREATE TABLE
  if (lex->sql_command != SQLCOM_CREATE_TABLE)
    return 1;
  // ... create like
  if (lex->create_info.like())
    return 1;
  // ... create select
  if (lex->select_lex.item_list.elements)
    return 1;
  // ... temporary
  if (create_info->tmp_table())
    return 1;
  // ... if exists
  if (lex->create_info.if_not_exists())
    return 1;

  // XXX error out or rather ignore the following:
  // ... partitioning
  if (lex->part_info)
    return 1;
  // ... union
  if (create_info->used_fields & HA_CREATE_USED_UNION)
    return 1;
  // ... index/data directory
  if (create_info->data_file_name || create_info->index_file_name)
    return 1;
  // ... engine
  DBUG_ASSERT(lex->m_sql_cmd);
  if (lex->create_info.used_fields & HA_CREATE_USED_ENGINE)
  {
    /*
      TODO: we could just compare engine names here, without resolving.
      But this optimization is too late for 10.1.
    */
    Storage_engine_name *opt= lex->m_sql_cmd->option_storage_engine_name();
    DBUG_ASSERT(opt); // lex->m_sql_cmd must be an Sql_cmd_create_table instance
    if (opt->resolve_storage_engine_with_error(thd, &create_info->db_type,
                                               false) ||
        (create_info->db_type && create_info->db_type != engine))
      return 1;
  }

  return 0;
}

int TABLE_SHARE::init_from_sql_statement_string(THD *thd, bool write,
                                        const char *sql, size_t sql_length)
{
  sql_mode_t saved_mode= thd->variables.sql_mode;
  CHARSET_INFO *old_cs= thd->variables.character_set_client;
  Parser_state parser_state;
  bool error;
  char *sql_copy;
  handler *file;
  LEX *old_lex;
  Query_arena *arena, backup;
  LEX tmp_lex;
  KEY *unused1;
  uint unused2;
  handlerton *hton= plugin_hton(db_plugin);
  LEX_CUSTRING frm= {0,0};
  LEX_STRING db_backup= { thd->db, thd->db_length };
  DBUG_ENTER("TABLE_SHARE::init_from_sql_statement_string");

  /*
    Ouch. Parser may *change* the string it's working on.
    Currently (2013-02-26) it is used to permanently disable
    conditional comments.
    Anyway, let's copy the caller's string...
  */
  if (!(sql_copy= thd->strmake(sql, sql_length)))
    DBUG_RETURN(HA_ERR_OUT_OF_MEM);

  if (parser_state.init(thd, sql_copy, sql_length))
    DBUG_RETURN(HA_ERR_OUT_OF_MEM);

  thd->variables.sql_mode= MODE_NO_ENGINE_SUBSTITUTION | MODE_NO_DIR_IN_CREATE;
  thd->variables.character_set_client= system_charset_info;
  tmp_disable_binlog(thd);
  old_lex= thd->lex;
  thd->lex= &tmp_lex;

  arena= thd->stmt_arena;
  if (arena->is_conventional())
    arena= 0;
  else
    thd->set_n_backup_active_arena(arena, &backup);

  thd->reset_db(db.str, db.length);
  lex_start(thd);

  if ((error= parse_sql(thd, & parser_state, NULL) || 
              sql_unusable_for_discovery(thd, hton, sql_copy)))
    goto ret;

  thd->lex->create_info.db_type= hton;
#ifdef WITH_PARTITION_STORAGE_ENGINE
  thd->work_part_info= 0;                       // For partitioning
#endif

  if (tabledef_version.str)
    thd->lex->create_info.tabledef_version= tabledef_version;

  promote_first_timestamp_column(&thd->lex->alter_info.create_list);
  file= mysql_create_frm_image(thd, db.str, table_name.str,
                               &thd->lex->create_info, &thd->lex->alter_info,
                               C_ORDINARY_CREATE, &unused1, &unused2, &frm);
  error|= file == 0;
  delete file;

  if (frm.str)
  {
    option_list= 0;             // cleanup existing options ...
    option_struct= 0;           // ... if it's an assisted discovery
    error= init_from_binary_frm_image(thd, write, frm.str, frm.length);
  }

ret:
  my_free(const_cast<uchar*>(frm.str));
  lex_end(thd->lex);
  thd->reset_db(db_backup.str, db_backup.length);
  thd->lex= old_lex;
  if (arena)
    thd->restore_active_arena(arena, &backup);
  reenable_binlog(thd);
  thd->variables.sql_mode= saved_mode;
  thd->variables.character_set_client= old_cs;
  if (thd->is_error() || error)
  {
    thd->clear_error();
    my_error(ER_SQL_DISCOVER_ERROR, MYF(0),
             plugin_name(db_plugin)->str, db.str, table_name.str,
             sql_copy);
    DBUG_RETURN(HA_ERR_GENERIC);
  }
  DBUG_RETURN(0);
}

bool TABLE_SHARE::write_frm_image(const uchar *frm, size_t len)
{
  return writefrm(normalized_path.str, db.str, table_name.str, false, frm, len);
}


bool TABLE_SHARE::read_frm_image(const uchar **frm, size_t *len)
{
  if (IF_PARTITIONING(partition_info_str, 0))   // cannot discover a partition
  {
    DBUG_ASSERT(db_type()->discover_table == 0);
    return 1;
  }

  if (frm_image)
  {
    *frm= frm_image->str;
    *len= frm_image->length;
    frm_image->str= 0; // pass the ownership to the caller
    frm_image= 0;
    return 0;
  }
  return readfrm(normalized_path.str, frm, len);
}


void TABLE_SHARE::free_frm_image(const uchar *frm)
{
  if (frm)
    my_free(const_cast<uchar*>(frm));
}


static bool fix_vcol_expr(THD *thd, Virtual_column_info *vcol)
{
  DBUG_ENTER("fix_vcol_expr");

  const enum enum_mark_columns save_mark_used_columns= thd->mark_used_columns;
  thd->mark_used_columns= MARK_COLUMNS_NONE;

  int error= vcol->expr->fix_fields(thd, &vcol->expr);

  thd->mark_used_columns= save_mark_used_columns;

  if (unlikely(error))
  {
    StringBuffer<MAX_FIELD_WIDTH> str;
    vcol->print(&str);
    my_error(ER_ERROR_EVALUATING_EXPRESSION, MYF(0), str.c_ptr_safe());
    DBUG_RETURN(1);
  }

  DBUG_RETURN(0);
}

/** rerun fix_fields for vcols that returns time- or session- dependent values

    @note this is done for all vcols for INSERT/UPDATE/DELETE,
    and only as needed for SELECTs.
*/
bool fix_session_vcol_expr(THD *thd, Virtual_column_info *vcol)
{
  DBUG_ENTER("fix_session_vcol_expr");
  if (!(vcol->flags & (VCOL_TIME_FUNC|VCOL_SESSION_FUNC)))
    DBUG_RETURN(0);

  vcol->expr->walk(&Item::cleanup_excluding_fields_processor, 0, 0);
  DBUG_ASSERT(!vcol->expr->fixed);
  DBUG_RETURN(fix_vcol_expr(thd, vcol));
}


/** invoke fix_session_vcol_expr for a vcol

    @note this is called for generated column or a DEFAULT expression from
    their corresponding fix_fields on SELECT.
*/
bool fix_session_vcol_expr_for_read(THD *thd, Field *field,
                                    Virtual_column_info *vcol)
{
  DBUG_ENTER("fix_session_vcol_expr_for_read");
  TABLE_LIST *tl= field->table->pos_in_table_list;
  if (!tl || tl->lock_type >= TL_WRITE_ALLOW_WRITE)
    DBUG_RETURN(0);
  Security_context *save_security_ctx= thd->security_ctx;
  if (tl->security_ctx)
    thd->security_ctx= tl->security_ctx;
  bool res= fix_session_vcol_expr(thd, vcol);
  thd->security_ctx= save_security_ctx;
  DBUG_RETURN(res);
}


/*
  @brief 
    Perform semantic analysis of the defining expression for a virtual column

  @param thd        The thread object
  @param table      The table containing the virtual column
  @param field	    Field if this is a DEFAULT or AS, otherwise NULL
  @param vcol       The Virtual_column object


  @details
    The function performs semantic analysis of the defining expression for
    the virtual column vcol_field. The expression is used to compute the
    values of this column.

  @retval
    TRUE           An error occurred, something was wrong with the function
  @retval
    FALSE          Otherwise
*/

static bool fix_and_check_vcol_expr(THD *thd, TABLE *table,
                                    Virtual_column_info *vcol)
{
  Item* func_expr= vcol->expr;
  DBUG_ENTER("fix_and_check_vcol_expr");
  DBUG_PRINT("info", ("vcol: %p", vcol));
  DBUG_ASSERT(func_expr);

  if (func_expr->fixed)
    DBUG_RETURN(0); // nothing to do

  if (fix_vcol_expr(thd, vcol))
    DBUG_RETURN(1);

  if (vcol->flags)
    DBUG_RETURN(0); // already checked, no need to do it again

  /* fix_fields could've changed the expression */
  func_expr= vcol->expr;

  /* this was checked in check_expression(), but the frm could be mangled... */
  if (unlikely(func_expr->result_type() == ROW_RESULT))
  {
    my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
    DBUG_RETURN(1);
  }

  /*
    Walk through the Item tree checking if all items are valid
    to be part of the virtual column
  */
  Item::vcol_func_processor_result res;
  res.errors= 0;

  int error= func_expr->walk(&Item::check_vcol_func_processor, 0, &res);
  if (error || (res.errors & VCOL_IMPOSSIBLE))
  {
    // this can only happen if the frm was corrupted
    my_error(ER_VIRTUAL_COLUMN_FUNCTION_IS_NOT_ALLOWED, MYF(0), res.name,
             vcol->get_vcol_type_name(), vcol->name.str);
    DBUG_RETURN(1);
  }
  else if (res.errors & VCOL_AUTO_INC)
  {
    /*
      An auto_increment field may not be used in an expression for
      a check constraint, a default value or a generated column

      Note that this error condition is not detected during parsing
      of the statement because the field item does not have a field
      pointer at that time
    */
    myf warn= table->s->frm_version < FRM_VER_EXPRESSSIONS ? ME_JUST_WARNING : 0;
    my_error(ER_VIRTUAL_COLUMN_FUNCTION_IS_NOT_ALLOWED, MYF(warn),
             "AUTO_INCREMENT", vcol->get_vcol_type_name(), res.name);
    if (!warn)
      DBUG_RETURN(1);
  }
  vcol->flags= res.errors;

  if (vcol->flags & VCOL_SESSION_FUNC)
    table->s->vcols_need_refixing= true;

  DBUG_RETURN(0);
}


/*
  @brief
    Unpack the definition of a virtual column from its linear representation

  @param thd             The thread object
  @param mem_root        Where to allocate memory
  @param table           The table containing the virtual column
  @param field           Field if this is a DEFAULT or AS, otherwise NULL
  @param vcol            The Virtual_column object
  @param[out] error_reported   Flag to inform the caller that no
                               other error messages are to be generated

  @details

    The function takes string expression from the 'vcol' object of the
    table 'table' and parses it, building an item object for it. The
    pointer to this item is placed into in a Virtual_column_info object
    that is created. After this the function performs
    semantic analysis of the item by calling the the function
    fix_and_check_vcol_expr().  Since the defining expression is part of the table
    definition the item for it is created in table->memroot within the
    special arena TABLE::expr_arena or in the thd memroot for INSERT DELAYED

  @note
    Before passing 'vcol_expr' to the parser the function wraps it in
    parentheses and prepends a special keyword.
  
   @retval Virtual_column_info*   Success
   @retval NULL                   Error
*/

static Virtual_column_info *
unpack_vcol_info_from_frm(THD *thd, MEM_ROOT *mem_root, TABLE *table,
                          String *expr_str, Virtual_column_info **vcol_ptr,
                          bool *error_reported)
{
  Create_field vcol_storage; // placeholder for vcol_info
  Parser_state parser_state;
  Virtual_column_info *vcol= *vcol_ptr, *vcol_info= 0;
  LEX *old_lex= thd->lex;
  LEX lex;
  bool error;
  DBUG_ENTER("unpack_vcol_info_from_frm");

  DBUG_ASSERT(vcol->expr == NULL);
  
  if (parser_state.init(thd, expr_str->c_ptr_safe(), expr_str->length()))
    goto end;

  if (init_lex_with_single_table(thd, table, &lex))
    goto end;

  lex.parse_vcol_expr= true;
  lex.last_field= &vcol_storage;

  error= parse_sql(thd, &parser_state, NULL);
  if (error)
    goto end;

  vcol_storage.vcol_info->set_vcol_type(vcol->get_vcol_type());
  vcol_storage.vcol_info->stored_in_db=      vcol->stored_in_db;
  vcol_storage.vcol_info->name=              vcol->name;
  vcol_storage.vcol_info->utf8=              vcol->utf8;
  if (!fix_and_check_vcol_expr(thd, table, vcol_storage.vcol_info))
  {
    *vcol_ptr= vcol_info= vcol_storage.vcol_info;   // Expression ok
    DBUG_ASSERT(vcol_info->expr);
    goto end;
  }
  *error_reported= TRUE;

end:
  end_lex_with_single_table(thd, table, old_lex);

  DBUG_RETURN(vcol_info);
}

static bool check_vcol_forward_refs(Field *field, Virtual_column_info *vcol)
{
  bool res= vcol &&
            vcol->expr->walk(&Item::check_field_expression_processor, 0,
                                  field);
  return res;
}

/*
  Open a table based on a TABLE_SHARE

  SYNOPSIS
    open_table_from_share()
    thd			Thread handler
    share		Table definition
    alias       	Alias for table
    db_stat		open flags (for example HA_OPEN_KEYFILE|
    			HA_OPEN_RNDFILE..) can be 0 (example in
                        ha_example_table)
    prgflag   		READ_ALL etc..
    ha_open_flags	HA_OPEN_ABORT_IF_LOCKED etc..
    outparam       	result table

  RETURN VALUES
   0	ok
   1	Error (see open_table_error)
   2    Error (see open_table_error)
   3    Wrong data in .frm file
   4    Error (see open_table_error)
   5    Error (see open_table_error: charset unavailable)
   7    Table definition has changed in engine
*/

enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
                       const char *alias, uint db_stat, uint prgflag,
                       uint ha_open_flags, TABLE *outparam,
                       bool is_create_table)
{
  enum open_frm_error error;
  uint records, i, bitmap_size, bitmap_count;
  size_t tmp_length;
  const char *tmp_alias;
  bool error_reported= FALSE;
  uchar *record, *bitmaps;
  Field **field_ptr;
  uint8 save_context_analysis_only= thd->lex->context_analysis_only;
  TABLE_SHARE::enum_v_keys check_set_initialized= share->check_set_initialized;
  DBUG_ENTER("open_table_from_share");
  DBUG_PRINT("enter",("name: '%s.%s'  form: %p", share->db.str,
                      share->table_name.str, outparam));

  thd->lex->context_analysis_only&= ~CONTEXT_ANALYSIS_ONLY_VIEW; // not a view

  error= OPEN_FRM_ERROR_ALREADY_ISSUED; // for OOM errors below
  bzero((char*) outparam, sizeof(*outparam));
  outparam->in_use= thd;
  outparam->s= share;
  outparam->db_stat= db_stat;
  outparam->write_row_record= NULL;

  if (share->incompatible_version &&
      !(ha_open_flags & (HA_OPEN_FOR_ALTER | HA_OPEN_FOR_REPAIR)))
  {
    /* one needs to run mysql_upgrade on the table */
    error= OPEN_FRM_NEEDS_REBUILD;
    goto err;
  }
  init_sql_alloc(&outparam->mem_root, TABLE_ALLOC_BLOCK_SIZE, 0, MYF(0));

  /*
    We have to store the original alias in mem_root as constraints and virtual
    functions may store pointers to it
  */
  tmp_length= strlen(alias);
  if (!(tmp_alias= strmake_root(&outparam->mem_root, alias, tmp_length)))
    goto err;

  outparam->alias.set(tmp_alias, tmp_length, table_alias_charset);
  outparam->quick_keys.init();
  outparam->covering_keys.init();
  outparam->intersect_keys.init();
  outparam->keys_in_use_for_query.init();

  /* Allocate handler */
  outparam->file= 0;
  if (!(prgflag & OPEN_FRM_FILE_ONLY))
  {
    if (!(outparam->file= get_new_handler(share, &outparam->mem_root,
                                          share->db_type())))
      goto err;

    if (outparam->file->set_ha_share_ref(&share->ha_share))
      goto err;
  }
  else
  {
    DBUG_ASSERT(!db_stat);
  }

  outparam->reginfo.lock_type= TL_UNLOCK;
  outparam->current_lock= F_UNLCK;
  records=0;
  if ((db_stat & HA_OPEN_KEYFILE) || (prgflag & DELAYED_OPEN))
    records=1;
  if (prgflag & (READ_ALL+EXTRA_RECORD))
    records++;

  if (!(record= (uchar*) alloc_root(&outparam->mem_root,
                                    share->rec_buff_length * records)))
    goto err;                                   /* purecov: inspected */
  MEM_NOACCESS(record, share->rec_buff_length * records);

  if (records == 0)
  {
    /* We are probably in hard repair, and the buffers should not be used */
    outparam->record[0]= outparam->record[1]= share->default_values;
  }
  else
  {
    outparam->record[0]= record;
    if (records > 1)
      outparam->record[1]= record+ share->rec_buff_length;
    else
      outparam->record[1]= outparam->record[0];   // Safety
  }
  MEM_UNDEFINED(outparam->record[0], share->reclength);
  MEM_UNDEFINED(outparam->record[1], share->reclength);

  if (!(field_ptr = (Field **) alloc_root(&outparam->mem_root,
                                          (uint) ((share->fields+1)*
                                                  sizeof(Field*)))))
    goto err;                                   /* purecov: inspected */

  outparam->field= field_ptr;

  record= (uchar*) outparam->record[0]-1;	/* Fieldstart = 1 */
  if (share->null_field_first)
    outparam->null_flags= (uchar*) record+1;
  else
    outparam->null_flags= (uchar*) (record+ 1+ share->reclength -
                                    share->null_bytes);

  /* Setup copy of fields from share, but use the right alias and record */
  for (i=0 ; i < share->fields; i++, field_ptr++)
  {
    if (!((*field_ptr)= share->field[i]->clone(&outparam->mem_root, outparam)))
      goto err;
  }
  (*field_ptr)= 0;                              // End marker

  DEBUG_SYNC(thd, "TABLE_after_field_clone");

  if (share->found_next_number_field)
    outparam->found_next_number_field=
      outparam->field[(uint) (share->found_next_number_field - share->field)];

  /* Fix key->name and key_part->field */
  if (share->key_parts)
  {
    KEY	*key_info, *key_info_end;
    KEY_PART_INFO *key_part;
    uint n_length;
    n_length= share->keys*sizeof(KEY) + share->ext_key_parts*sizeof(KEY_PART_INFO);
    if (!(key_info= (KEY*) alloc_root(&outparam->mem_root, n_length)))
      goto err;
    outparam->key_info= key_info;
    key_part= (reinterpret_cast<KEY_PART_INFO*>(key_info+share->keys));

    memcpy(key_info, share->key_info, sizeof(*key_info)*share->keys);
    memcpy(key_part, share->key_info[0].key_part, (sizeof(*key_part) *
                                                   share->ext_key_parts));

    for (key_info_end= key_info + share->keys ;
         key_info < key_info_end ;
         key_info++)
    {
      KEY_PART_INFO *key_part_end;

      key_info->table= outparam;
      key_info->key_part= key_part;

      key_part_end= key_part + (share->use_ext_keys ? key_info->ext_key_parts :
			                              key_info->user_defined_key_parts) ;
      for ( ; key_part < key_part_end; key_part++)
      {
        Field *field= key_part->field= outparam->field[key_part->fieldnr - 1];

        if (field->key_length() != key_part->length &&
            !(field->flags & BLOB_FLAG))
        {
          /*
            We are using only a prefix of the column as a key:
            Create a new field for the key part that matches the index
          */
          field= key_part->field=field->make_new_field(&outparam->mem_root,
                                                       outparam, 0);
          field->field_length= key_part->length;
        }
      }
      if (!share->use_ext_keys)
	key_part+= key_info->ext_key_parts - key_info->user_defined_key_parts;
    }
  }

  /*
    Process virtual and default columns, if any.
  */
  if (share->virtual_fields || share->default_fields ||
      share->default_expressions || share->table_check_constraints)
  {
    Field **vfield_ptr, **dfield_ptr;
    Virtual_column_info **check_constraint_ptr;

    if (!multi_alloc_root(&outparam->mem_root,
                          &vfield_ptr, (uint) ((share->virtual_fields + 1)*
                                               sizeof(Field*)),
                          &dfield_ptr, (uint) ((share->default_fields +
                                                share->default_expressions +1)*
                                               sizeof(Field*)),
                          &check_constraint_ptr,
                          (uint) ((share->table_check_constraints +
                                   share->field_check_constraints + 1)*
                                  sizeof(Virtual_column_info*)),
                          NullS))
      goto err;
    if (share->virtual_fields)
      outparam->vfield= vfield_ptr;
    if (share->default_fields + share->default_expressions)
      outparam->default_field= dfield_ptr;
    if (share->table_check_constraints || share->field_check_constraints)
      outparam->check_constraints= check_constraint_ptr;

    vcol_init_mode mode= VCOL_INIT_DEPENDENCY_FAILURE_IS_WARNING;
#if MYSQL_VERSION_ID > 100500
    switch (thd->lex->sql_command)
    {
    case SQLCOM_CREATE_TABLE:
      mode= VCOL_INIT_DEPENDENCY_FAILURE_IS_ERROR;
      break;
    case SQLCOM_ALTER_TABLE:
    case SQLCOM_CREATE_INDEX:
    case SQLCOM_DROP_INDEX:
      if ((ha_open_flags & HA_OPEN_FOR_ALTER) == 0)
        mode= VCOL_INIT_DEPENDENCY_FAILURE_IS_ERROR;
      break;
    default:
      break;
    }
#endif
    if (parse_vcol_defs(thd, &outparam->mem_root, outparam,
                        &error_reported, mode))
    {
      error= OPEN_FRM_CORRUPTED;
      goto err;
    }

    /* Update to use trigger fields */
    switch_defaults_to_nullable_trigger_fields(outparam);
  }

#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (share->partition_info_str_len && outparam->file)
  {
  /*
    In this execution we must avoid calling thd->change_item_tree since
    we might release memory before statement is completed. We do this
    by changing to a new statement arena. As part of this arena we also
    set the memory root to be the memory root of the table since we
    call the parser and fix_fields which both can allocate memory for
    item objects. We keep the arena to ensure that we can release the
    free_list when closing the table object.
    SEE Bug #21658
  */

    Query_arena *backup_stmt_arena_ptr= thd->stmt_arena;
    Query_arena backup_arena;
    Query_arena part_func_arena(&outparam->mem_root,
                                Query_arena::STMT_INITIALIZED);
    thd->set_n_backup_active_arena(&part_func_arena, &backup_arena);
    thd->stmt_arena= &part_func_arena;
    bool tmp;
    bool work_part_info_used;

    tmp= mysql_unpack_partition(thd, share->partition_info_str,
                                share->partition_info_str_len,
                                outparam, is_create_table,
                                plugin_hton(share->default_part_plugin),
                                &work_part_info_used);
    if (tmp)
    {
      thd->stmt_arena= backup_stmt_arena_ptr;
      thd->restore_active_arena(&part_func_arena, &backup_arena);
      goto partititon_err;
    }
    outparam->part_info->is_auto_partitioned= share->auto_partitioned;
    DBUG_PRINT("info", ("autopartitioned: %u", share->auto_partitioned));
    /* 
      We should perform the fix_partition_func in either local or
      caller's arena depending on work_part_info_used value.
    */
    if (!work_part_info_used)
      tmp= fix_partition_func(thd, outparam, is_create_table);
    thd->stmt_arena= backup_stmt_arena_ptr;
    thd->restore_active_arena(&part_func_arena, &backup_arena);
    if (!tmp)
    {
      if (work_part_info_used)
        tmp= fix_partition_func(thd, outparam, is_create_table);
    }
    outparam->part_info->item_free_list= part_func_arena.free_list;
partititon_err:
    if (tmp)
    {
      if (is_create_table)
      {
        /*
          During CREATE/ALTER TABLE it is ok to receive errors here.
          It is not ok if it happens during the opening of an frm
          file as part of a normal query.
        */
        error_reported= TRUE;
      }
      goto err;
    }
  }
#endif

  /* Check virtual columns against table's storage engine. */
  if (share->virtual_fields &&
        (outparam->file && 
          !(outparam->file->ha_table_flags() & HA_CAN_VIRTUAL_COLUMNS)))
  {
    my_error(ER_UNSUPPORTED_ENGINE_FOR_VIRTUAL_COLUMNS, MYF(0),
             plugin_name(share->db_plugin)->str);
    error_reported= TRUE;
    goto err;
  }

  /* Allocate bitmaps */

  bitmap_size= share->column_bitmap_size;
  bitmap_count= 7;
  if (share->virtual_fields)
    bitmap_count++;

  if (!(bitmaps= (uchar*) alloc_root(&outparam->mem_root,
                                     bitmap_size * bitmap_count)))
    goto err;

  my_bitmap_init(&outparam->def_read_set,
                 (my_bitmap_map*) bitmaps, share->fields, FALSE);
  bitmaps+= bitmap_size;
  my_bitmap_init(&outparam->def_write_set,
                 (my_bitmap_map*) bitmaps, share->fields, FALSE);
  bitmaps+= bitmap_size;

  /* Don't allocate vcol_bitmap if we don't need it */
  if (share->virtual_fields)
  {
    if (!(outparam->def_vcol_set= (MY_BITMAP*)
          alloc_root(&outparam->mem_root, sizeof(*outparam->def_vcol_set))))
      goto err;
    my_bitmap_init(outparam->def_vcol_set,
                   (my_bitmap_map*) bitmaps, share->fields, FALSE);
    bitmaps+= bitmap_size;
  }

  my_bitmap_init(&outparam->has_value_set,
                 (my_bitmap_map*) bitmaps, share->fields, FALSE);
  bitmaps+= bitmap_size;
  my_bitmap_init(&outparam->tmp_set,
                 (my_bitmap_map*) bitmaps, share->fields, FALSE);
  bitmaps+= bitmap_size;
  my_bitmap_init(&outparam->eq_join_set,
                 (my_bitmap_map*) bitmaps, share->fields, FALSE);
  bitmaps+= bitmap_size;
  my_bitmap_init(&outparam->cond_set,
                 (my_bitmap_map*) bitmaps, share->fields, FALSE);
  bitmaps+= bitmap_size;
  my_bitmap_init(&outparam->def_rpl_write_set,
                 (my_bitmap_map*) bitmaps, share->fields, FALSE);
  outparam->default_column_bitmaps();

  outparam->cond_selectivity= 1.0;

  /* The table struct is now initialized;  Open the table */
  if (db_stat)
  {
    if (specialflag & SPECIAL_WAIT_IF_LOCKED)
      ha_open_flags|= HA_OPEN_WAIT_IF_LOCKED;
    else
      ha_open_flags|= HA_OPEN_IGNORE_IF_LOCKED;

    int ha_err= outparam->file->ha_open(outparam, share->normalized_path.str,
                                 (db_stat & HA_READ_ONLY ? O_RDONLY : O_RDWR),
                                  ha_open_flags);
    if (ha_err)
    {
      share->open_errno= ha_err;
      /* Set a flag if the table is crashed and it can be auto. repaired */
      share->crashed= (outparam->file->auto_repair(ha_err) &&
                       !(ha_open_flags & HA_OPEN_FOR_REPAIR));
      outparam->file->print_error(ha_err, MYF(0));
      error_reported= TRUE;

      if (ha_err == HA_ERR_TABLE_DEF_CHANGED)
        error= OPEN_FRM_DISCOVER;

      /*
        We're here, because .frm file was successfully opened.

        But if the table doesn't exist in the engine and the engine
        supports discovery, we force rediscover to discover
        the fact that table doesn't in fact exist and remove
        the stray .frm file.
      */
      if (share->db_type()->discover_table &&
          (ha_err == ENOENT || ha_err == HA_ERR_NO_SUCH_TABLE))
        error= OPEN_FRM_DISCOVER;

      goto err;
    }
  }

  outparam->mark_columns_used_by_virtual_fields();
  if (!check_set_initialized &&
      share->check_set_initialized == TABLE_SHARE::V_KEYS)
  {
    // copy PART_INDIRECT_KEY_FLAG that was set meanwhile by *some* thread
    for (uint i= 0 ; i < share->fields ; i++)
    {
      if (share->field[i]->flags & PART_INDIRECT_KEY_FLAG)
        outparam->field[i]->flags|= PART_INDIRECT_KEY_FLAG;
    }
  }

  if (share->table_category == TABLE_CATEGORY_LOG)
  {
    outparam->no_replicate= TRUE;
  }
  else if (outparam->file)
  {
    handler::Table_flags flags= outparam->file->ha_table_flags();
    outparam->no_replicate= ! MY_TEST(flags & (HA_BINLOG_STMT_CAPABLE
                                               | HA_BINLOG_ROW_CAPABLE))
                            || MY_TEST(flags & HA_HAS_OWN_BINLOGGING);
  }
  else
  {
    outparam->no_replicate= FALSE;
  }

  if (outparam->no_replicate || !binlog_filter->db_ok(outparam->s->db.str))
    outparam->s->cached_row_logging_check= 0;   // No row based replication

  /* Increment the opened_tables counter, only when open flags set. */
  if (db_stat)
    thd->status_var.opened_tables++;

  thd->lex->context_analysis_only= save_context_analysis_only;
  DBUG_RETURN (OPEN_FRM_OK);

 err:
  if (! error_reported)
    open_table_error(share, error, my_errno);
  delete outparam->file;
#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (outparam->part_info)
    free_items(outparam->part_info->item_free_list);
#endif
  outparam->file= 0;				// For easier error checking
  outparam->db_stat=0;
  thd->lex->context_analysis_only= save_context_analysis_only;
  if (outparam->expr_arena)
    outparam->expr_arena->free_items();
  free_root(&outparam->mem_root, MYF(0));       // Safe to call on bzero'd root
  outparam->alias.free();
  DBUG_RETURN (error);
}


/*
  Free information allocated by openfrm

  SYNOPSIS
    closefrm()
    table		TABLE object to free
*/

int closefrm(TABLE *table)
{
  int error=0;
  DBUG_ENTER("closefrm");
  DBUG_PRINT("enter", ("table: %p", table));

  if (table->db_stat)
    error=table->file->ha_close();
  table->alias.free();
  if (table->expr_arena)
    table->expr_arena->free_items();
  if (table->field)
  {
    for (Field **ptr=table->field ; *ptr ; ptr++)
    {
      delete *ptr;
    }
    table->field= 0;
  }
  delete table->file;
  table->file= 0;				/* For easier errorchecking */
#ifdef WITH_PARTITION_STORAGE_ENGINE
  if (table->part_info)
  {
    /* Allocated through table->mem_root, freed below */
    free_items(table->part_info->item_free_list);
    table->part_info->item_free_list= 0;
    table->part_info= 0;
  }
#endif
  free_root(&table->mem_root, MYF(0));
  DBUG_RETURN(error);
}


/* Deallocate temporary blob storage */

void free_blobs(TABLE *table)
{
  uint *ptr, *end;
  for (ptr= table->s->blob_field, end=ptr + table->s->blob_fields ;
       ptr != end ;
       ptr++)
  {
    /*
      Reduced TABLE objects which are used by row-based replication for
      type conversion might have some fields missing. Skip freeing BLOB
      buffers for such missing fields.
    */
    if (table->field[*ptr])
      ((Field_blob*) table->field[*ptr])->free();
  }
}


/**
  Reclaim temporary blob storage which is bigger than 
  a threshold.
 
  @param table A handle to the TABLE object containing blob fields
  @param size The threshold value.
 
*/

void free_field_buffers_larger_than(TABLE *table, uint32 size)
{
  uint *ptr, *end;
  for (ptr= table->s->blob_field, end=ptr + table->s->blob_fields ;
       ptr != end ;
       ptr++)
  {
    Field_blob *blob= (Field_blob*) table->field[*ptr];
    if (blob->get_field_buffer_size() > size)
        blob->free();
  }
}

/* error message when opening a form file */

void open_table_error(TABLE_SHARE *share, enum open_frm_error error,
                      int db_errno)
{
  char buff[FN_REFLEN];
  const myf errortype= ME_ERROR+ME_WAITTANG;  // Write fatals error to log
  DBUG_ENTER("open_table_error");
  DBUG_PRINT("info", ("error: %d  db_errno: %d", error, db_errno));

  switch (error) {
  case OPEN_FRM_OPEN_ERROR:
    /*
      Test if file didn't exists. We have to also test for EINVAL as this
      may happen on windows when opening a file with a not legal file name
    */
    if (db_errno == ENOENT || db_errno == EINVAL)
      my_error(ER_NO_SUCH_TABLE, MYF(0), share->db.str, share->table_name.str);
    else
    {
      strxmov(buff, share->normalized_path.str, reg_ext, NullS);
      my_error((db_errno == EMFILE) ? ER_CANT_OPEN_FILE : ER_FILE_NOT_FOUND,
               errortype, buff, db_errno);
    }
    break;
  case OPEN_FRM_OK:
    DBUG_ASSERT(0); // open_table_error() is never called for this one
    break;
  case OPEN_FRM_ERROR_ALREADY_ISSUED:
    break;
  case OPEN_FRM_NOT_A_VIEW:
    my_error(ER_WRONG_OBJECT, MYF(0), share->db.str,
             share->table_name.str, "VIEW");
    break;
  case OPEN_FRM_NOT_A_TABLE:
    my_error(ER_WRONG_OBJECT, MYF(0), share->db.str,
             share->table_name.str, "TABLE");
    break;
  case OPEN_FRM_DISCOVER:
    DBUG_ASSERT(0); // open_table_error() is never called for this one
    break;
  case OPEN_FRM_CORRUPTED:
    strxmov(buff, share->normalized_path.str, reg_ext, NullS);
    my_error(ER_NOT_FORM_FILE, errortype, buff);
    break;
  case OPEN_FRM_READ_ERROR:
    strxmov(buff, share->normalized_path.str, reg_ext, NullS);
    my_error(ER_ERROR_ON_READ, errortype, buff, db_errno);
    break;
  case OPEN_FRM_NEEDS_REBUILD:
    strxnmov(buff, sizeof(buff)-1,
             share->db.str, ".", share->table_name.str, NullS);
    my_error(ER_TABLE_NEEDS_REBUILD, errortype, buff);
    break;
  }
  DBUG_VOID_RETURN;
} /* open_table_error */


	/*
	** fix a str_type to a array type
	** typeparts separated with some char. differents types are separated
	** with a '\0'
	*/

static bool
fix_type_pointers(const char ***typelib_value_names,
                  uint **typelib_value_lengths,
                  TYPELIB *point_to_type, uint types,
                  char *ptr, size_t length)
{
  const char *end= ptr + length;

  while (types--)
  {
    char sep;
    point_to_type->name=0;
    point_to_type->type_names= *typelib_value_names;
    point_to_type->type_lengths= *typelib_value_lengths;

    /*
      Typelib can be encoded as:
      1) 0x00                     - empty typelib
      2) 0xFF 0x00                - empty typelib (index names)
      3) sep (value sep)... 0x00  - non-empty typelib (where sep is a separator)
    */
    if (length == 2 && ptr[0] == (char) 0xFF && ptr[1] == '\0')
    {
      /*
        This is a special case #2.
        If there are no indexes at all, index names can be encoded
        as a two byte sequence: 0xFF 0x00
        TODO: Check if it's a bug in the FRM packing routine.
        It should probably write just 0x00 instead of 0xFF00.
      */
      ptr+= 2;
    }
    else if ((sep= *ptr++))            // A non-empty typelib
    {
      for ( ; ptr < end; )
      {
        // Now scan the next value+sep pair
        char *vend= (char*) memchr(ptr, sep, end - ptr);
        if (!vend)
          return true;            // Bad format
        *((*typelib_value_names)++)= ptr;
        *((*typelib_value_lengths)++)= vend - ptr;
        *vend= '\0';              // Change sep to '\0'
        ptr= vend + 1;            // Shift from sep to the next byte
        /*
          Now we can have either:
          - the end-of-typelib marker (0x00)
          - more value+sep pairs
        */
        if (!*ptr)
        {
          /*
            We have an ambiguity here. 0x00 can be an end-of-typelib marker,
            but it can also be a part of the next value:
              CREATE TABLE t1 (a ENUM(0x61, 0x0062) CHARACTER SET BINARY);
            If this is the last ENUM/SET in the table and there is still more
            packed data left after 0x00, then we know for sure that 0x00
            is a part of the next value.
            TODO-10.5+: we should eventually introduce a new unambiguous
            typelib encoding for FRM.
          */
          if (!types && ptr + 1 < end)
            continue;           // A binary value starting with 0x00
          ptr++;                // Consume the end-of-typelib marker
          break;                // End of the current typelib
        }
      }
    }
    point_to_type->count= (uint) (*typelib_value_names -
                                  point_to_type->type_names);
    point_to_type++;
    *((*typelib_value_names)++)= NullS; /* End of type */
    *((*typelib_value_lengths)++)= 0;   /* End of type */
  }
  return ptr != end;
} /* fix_type_pointers */


TYPELIB *typelib(MEM_ROOT *mem_root, List<String> &strings)
{
  TYPELIB *result= (TYPELIB*) alloc_root(mem_root, sizeof(TYPELIB));
  if (!result)
    return 0;
  result->count=strings.elements;
  result->name="";
  uint nbytes= (sizeof(char*) + sizeof(uint)) * (result->count + 1);
  if (!(result->type_names= (const char**) alloc_root(mem_root, nbytes)))
    return 0;
  result->type_lengths= (uint*) (result->type_names + result->count + 1);
  List_iterator<String> it(strings);
  String *tmp;
  for (uint i=0; (tmp=it++) ; i++)
  {
    result->type_names[i]= tmp->ptr();
    result->type_lengths[i]= tmp->length();
  }
  result->type_names[result->count]= 0;		// End marker
  result->type_lengths[result->count]= 0;
  return result;
}


/*
 Search after a field with given start & length
 If an exact field isn't found, return longest field with starts
 at right position.
 
 NOTES
   This is needed because in some .frm fields 'fieldnr' was saved wrong

 RETURN
   0  error
   #  field number +1
*/

static uint find_field(Field **fields, uchar *record, uint start, uint length)
{
  Field **field;
  uint i, pos;

  pos= 0;
  for (field= fields, i=1 ; *field ; i++,field++)
  {
    if ((*field)->offset(record) == start)
    {
      if ((*field)->key_length() == length)
	return (i);
      if (!pos || fields[pos-1]->pack_length() <
	  (*field)->pack_length())
	pos= i;
    }
  }
  return (pos);
}


/*
  Store an SQL quoted string.

  SYNOPSIS  
    append_unescaped()
    res		result String
    pos		string to be quoted
    length	it's length

  NOTE
    This function works correctly with utf8 or single-byte charset strings.
    May fail with some multibyte charsets though.
*/

void append_unescaped(String *res, const char *pos, uint length)
{
  const char *end= pos+length;
  res->append('\'');

  for (; pos != end ; pos++)
  {
#if defined(USE_MB) && MYSQL_VERSION_ID < 40100
    uint mblen;
    if (use_mb(default_charset_info) &&
        (mblen= my_ismbchar(default_charset_info, pos, end)))
    {
      res->append(pos, mblen);
      pos+= mblen;
      continue;
    }
#endif

    switch (*pos) {
    case 0:				/* Must be escaped for 'mysql' */
      res->append('\\');
      res->append('0');
      break;
    case '\n':				/* Must be escaped for logs */
      res->append('\\');
      res->append('n');
      break;
    case '\r':
      res->append('\\');		/* This gives better readability */
      res->append('r');
      break;
    case '\\':
      res->append('\\');		/* Because of the sql syntax */
      res->append('\\');
      break;
    case '\'':
      res->append('\'');		/* Because of the sql syntax */
      res->append('\'');
      break;
    default:
      res->append(*pos);
      break;
    }
  }
  res->append('\'');
}


void prepare_frm_header(THD *thd, uint reclength, uchar *fileinfo,
                        HA_CREATE_INFO *create_info, uint keys, KEY *key_info)
{
  ulong key_comment_total_bytes= 0;
  uint i;
  DBUG_ENTER("prepare_frm_header");

  /* Fix this when we have new .frm files;  Current limit is 4G rows (TODO) */
  if (create_info->max_rows > UINT_MAX32)
    create_info->max_rows= UINT_MAX32;
  if (create_info->min_rows > UINT_MAX32)
    create_info->min_rows= UINT_MAX32;

  uint key_length, tmp_key_length, tmp, csid;
  bzero((char*) fileinfo, FRM_HEADER_SIZE);
  /* header */
  fileinfo[0]=(uchar) 254;
  fileinfo[1]= 1;
  fileinfo[2]= (create_info->expression_length == 0 ? FRM_VER_TRUE_VARCHAR :
                FRM_VER_EXPRESSSIONS);

  DBUG_ASSERT(ha_storage_engine_is_enabled(create_info->db_type));
  fileinfo[3]= (uchar) ha_legacy_type(create_info->db_type);

  /*
    Keep in sync with pack_keys() in unireg.cc
    For each key:
    8 bytes for the key header
    9 bytes for each key-part (MAX_REF_PARTS)
    NAME_LEN bytes for the name
    1 byte for the NAMES_SEP_CHAR (before the name)
    For all keys:
    6 bytes for the header
    1 byte for the NAMES_SEP_CHAR (after the last name)
    9 extra bytes (padding for safety? alignment?)
  */
  for (i= 0; i < keys; i++)
  {
    DBUG_ASSERT(MY_TEST(key_info[i].flags & HA_USES_COMMENT) ==
                (key_info[i].comment.length > 0));
    if (key_info[i].flags & HA_USES_COMMENT)
      key_comment_total_bytes += 2 + key_info[i].comment.length;
  }

  key_length= keys * (8 + MAX_REF_PARTS * 9 + NAME_LEN + 1) + 16
              + key_comment_total_bytes;

  int2store(fileinfo+8,1);
  tmp_key_length= (key_length < 0xffff) ? key_length : 0xffff;
  int2store(fileinfo+14,tmp_key_length);
  int2store(fileinfo+16,reclength);
  int4store(fileinfo+18,create_info->max_rows);
  int4store(fileinfo+22,create_info->min_rows);
  /* fileinfo[26] is set in mysql_create_frm() */
  fileinfo[27]=2;				// Use long pack-fields
  /* fileinfo[28 & 29] is set to key_info_length in mysql_create_frm() */
  create_info->table_options|=HA_OPTION_LONG_BLOB_PTR; // Use portable blob pointers
  int2store(fileinfo+30,create_info->table_options);
  fileinfo[32]=0;				// No filename anymore
  fileinfo[33]=5;                             // Mark for 5.0 frm file
  int4store(fileinfo+34,create_info->avg_row_length);
  csid= (create_info->default_table_charset ?
         create_info->default_table_charset->number : 0);
  fileinfo[38]= (uchar) csid;
  fileinfo[39]= (uchar) ((uint) create_info->transactional |
                         ((uint) create_info->page_checksum << 2));
  fileinfo[40]= (uchar) create_info->row_type;
  /* Bytes 41-46 were for RAID support; now reused for other purposes */
  fileinfo[41]= (uchar) (csid >> 8);
  int2store(fileinfo+42, create_info->stats_sample_pages & 0xffff);
  fileinfo[44]= (uchar)  create_info->stats_auto_recalc;
  int2store(fileinfo+45, (create_info->check_constraint_list->elements+
                          create_info->field_check_constraints));
  int4store(fileinfo+47, key_length);
  tmp= MYSQL_VERSION_ID;          // Store to avoid warning from int4store
  int4store(fileinfo+51, tmp);
  int4store(fileinfo+55, create_info->extra_size);
  /*
    59-60 is unused since 10.2.4
    61 for default_part_db_type
  */
  int2store(fileinfo+62, create_info->key_block_size);
  DBUG_VOID_RETURN;
} /* prepare_fileinfo */


void update_create_info_from_table(HA_CREATE_INFO *create_info, TABLE *table)
{
  TABLE_SHARE *share= table->s;
  DBUG_ENTER("update_create_info_from_table");

  create_info->max_rows= share->max_rows;
  create_info->min_rows= share->min_rows;
  create_info->table_options= share->db_create_options;
  create_info->avg_row_length= share->avg_row_length;
  create_info->row_type= share->row_type;
  create_info->key_block_size= share->key_block_size;
  create_info->default_table_charset= share->table_charset;
  create_info->table_charset= 0;
  create_info->comment= share->comment;
  create_info->transactional= share->transactional;
  create_info->page_checksum= share->page_checksum;
  create_info->option_list= share->option_list;

  DBUG_VOID_RETURN;
}

int
rename_file_ext(const char * from,const char * to,const char * ext)
{
  char from_b[FN_REFLEN],to_b[FN_REFLEN];
  (void) strxmov(from_b,from,ext,NullS);
  (void) strxmov(to_b,to,ext,NullS);
  return mysql_file_rename(key_file_frm, from_b, to_b, MYF(0));
}


/*
  Allocate string field in MEM_ROOT and return it as String

  SYNOPSIS
    get_field()
    mem   	MEM_ROOT for allocating
    field 	Field for retrieving of string
    res         result String

  RETURN VALUES
    1   string is empty
    0	all ok
*/

bool get_field(MEM_ROOT *mem, Field *field, String *res)
{
  char *to;
  StringBuffer<MAX_FIELD_WIDTH> str;
  bool rc;
  THD *thd= field->get_thd();
  sql_mode_t sql_mode_backup= thd->variables.sql_mode;
  thd->variables.sql_mode&= ~MODE_PAD_CHAR_TO_FULL_LENGTH;

  field->val_str(&str);
  if ((rc= !str.length() ||
           !(to= strmake_root(mem, str.ptr(), str.length()))))
  {
    res->length(0);
    goto ex;
  }
  res->set(to, str.length(), field->charset());

ex:
  thd->variables.sql_mode= sql_mode_backup;
  return rc;
}


/*
  Allocate string field in MEM_ROOT and return it as NULL-terminated string

  SYNOPSIS
    get_field()
    mem   	MEM_ROOT for allocating
    field 	Field for retrieving of string

  RETURN VALUES
    NullS  string is empty
    #      pointer to NULL-terminated string value of field
*/

char *get_field(MEM_ROOT *mem, Field *field)
{
  String str;
  bool rc= get_field(mem, field, &str);
  DBUG_ASSERT(rc || str.ptr()[str.length()] == '\0');
  return  rc ? NullS : (char *) str.ptr();
}

/*
  DESCRIPTION
    given a buffer with a key value, and a map of keyparts
    that are present in this value, returns the length of the value
*/
uint calculate_key_len(TABLE *table, uint key, const uchar *buf,
                       key_part_map keypart_map)
{
  /* works only with key prefixes */
  DBUG_ASSERT(((keypart_map + 1) & keypart_map) == 0);

  KEY *key_info= table->s->key_info+key;
  KEY_PART_INFO *key_part= key_info->key_part;
  KEY_PART_INFO *end_key_part= key_part + table->actual_n_key_parts(key_info);
  uint length= 0;

  while (key_part < end_key_part && keypart_map)
  {
    length+= key_part->store_length;
    keypart_map >>= 1;
    key_part++;
  }
  return length;
}

#ifndef DBUG_OFF
/**
  Verifies that database/table name is in lowercase, when it should be

  This is supposed to be used only inside DBUG_ASSERT()
*/
bool ok_for_lower_case_names(const char *name)
{
  if (!lower_case_table_names || !name)
    return true;

  char buf[SAFE_NAME_LEN];
  strmake_buf(buf, name);
  my_casedn_str(files_charset_info, buf);
  return strcmp(name, buf) == 0;
}
#endif

/*
  Check if database name is valid

  SYNPOSIS
    check_db_name()
    org_name		Name of database

  NOTES
    If lower_case_table_names is set to 1 then database name is converted
    to lower case

  RETURN
    0	ok
    1   error
*/

bool check_db_name(LEX_STRING *org_name)
{
  char *name= org_name->str;
  uint name_length= org_name->length;
  bool check_for_path_chars;

  if ((check_for_path_chars= check_mysql50_prefix(name)))
  {
    name+= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
    name_length-= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
  }

  if (!name_length || name_length > NAME_LEN)
    return 1;

  if (lower_case_table_names == 1 && name != any_db)
  {
    org_name->length= name_length= my_casedn_str(files_charset_info, name);
    if (check_for_path_chars)
      org_name->length+= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
  }
  if (db_name_is_in_ignore_db_dirs_list(name))
    return 1;

  return check_table_name(name, name_length, check_for_path_chars);
}


/*
  Allow anything as a table name, as long as it doesn't contain an
  ' ' at the end
  returns 1 on error
*/

bool check_table_name(const char *name, size_t length, bool check_for_path_chars)
{
  // name length in symbols
  size_t name_length= 0;
  const char *end= name+length;


  if (!check_for_path_chars &&
      (check_for_path_chars= check_mysql50_prefix(name)))
  {
    name+= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
    length-= MYSQL50_TABLE_NAME_PREFIX_LENGTH;
  }

  if (!length || length > NAME_LEN)
    return 1;
#if defined(USE_MB) && defined(USE_MB_IDENT)
  bool last_char_is_space= FALSE;
#else
  if (name[length-1]==' ')
    return 1;
#endif

  while (name != end)
  {
#if defined(USE_MB) && defined(USE_MB_IDENT)
    last_char_is_space= my_isspace(system_charset_info, *name);
    if (use_mb(system_charset_info))
    {
      int len=my_ismbchar(system_charset_info, name, end);
      if (len)
      {
        name+= len;
        name_length++;
        continue;
      }
    }
#endif
    if (check_for_path_chars &&
        (*name == '/' || *name == '\\' || *name == '~' || *name == FN_EXTCHAR))
      return 1;
    name++;
    name_length++;
  }
#if defined(USE_MB) && defined(USE_MB_IDENT)
  return last_char_is_space || (name_length > NAME_CHAR_LEN);
#else
  return FALSE;
#endif
}


bool check_column_name(const char *name)
{
  // name length in symbols
  size_t name_length= 0;
  bool last_char_is_space= TRUE;

  while (*name)
  {
#if defined(USE_MB) && defined(USE_MB_IDENT)
    last_char_is_space= my_isspace(system_charset_info, *name);
    if (use_mb(system_charset_info))
    {
      int len=my_ismbchar(system_charset_info, name, 
                          name+system_charset_info->mbmaxlen);
      if (len)
      {
        name += len;
        name_length++;
        continue;
      }
    }
#else
    last_char_is_space= *name==' ';
    if (*name == '\377')
      return 1;
#endif
    name++;
    name_length++;
  }
  /* Error if empty or too long column name */
  return last_char_is_space || (name_length > NAME_CHAR_LEN);
}


/**
  Checks whether a table is intact. Should be done *just* after the table has
  been opened.

  @param[in] table             The table to check
  @param[in] table_def         Expected structure of the table (column name
                               and type)

  @retval  FALSE  OK
  @retval  TRUE   There was an error. An error message is output
                  to the error log.  We do not push an error
                  message into the error stack because this
                  function is currently only called at start up,
                  and such errors never reach the user.
*/

bool
Table_check_intact::check(TABLE *table, const TABLE_FIELD_DEF *table_def)
{
  uint i;
  my_bool error= FALSE;
  const TABLE_FIELD_TYPE *field_def= table_def->field;
  DBUG_ENTER("table_check_intact");
  DBUG_PRINT("info",("table: %s  expected_count: %d",
                     table->alias.c_ptr(), table_def->count));

  /* Whether the table definition has already been validated. */
  if (table->s->table_field_def_cache == table_def)
    goto end;

  if (table->s->fields != table_def->count)
  {
    THD *thd= current_thd;
    DBUG_PRINT("info", ("Column count has changed, checking the definition"));

    /* previous MySQL version */
    if (MYSQL_VERSION_ID > table->s->mysql_version)
    {
      report_error(ER_COL_COUNT_DOESNT_MATCH_PLEASE_UPDATE,
                   ER_THD(thd, ER_COL_COUNT_DOESNT_MATCH_PLEASE_UPDATE),
                   table->alias.c_ptr(), table_def->count, table->s->fields,
                   static_cast<int>(table->s->mysql_version),
                   MYSQL_VERSION_ID);
      DBUG_RETURN(TRUE);
    }
    else if (MYSQL_VERSION_ID == table->s->mysql_version)
    {
      report_error(ER_COL_COUNT_DOESNT_MATCH_CORRUPTED_V2,
                   ER_THD(thd, ER_COL_COUNT_DOESNT_MATCH_CORRUPTED_V2),
                   table->s->db.str, table->s->table_name.str,
                   table_def->count, table->s->fields);
      DBUG_RETURN(TRUE);
    }
    /*
      Something has definitely changed, but we're running an older
      version of MySQL with new system tables.
      Let's check column definitions. If a column was added at
      the end of the table, then we don't care much since such change
      is backward compatible.
    */
  }
  else
  {
  StringBuffer<1024> sql_type(system_charset_info);
  sql_type.extra_allocation(256); // Allocate min 256 characters at once
  for (i=0 ; i < table_def->count; i++, field_def++)
  {
    sql_type.length(0);
    if (i < table->s->fields)
    {
      Field *field= table->field[i];

      if (strncmp(field->field_name, field_def->name.str,
                  field_def->name.length))
      {
        /*
          Name changes are not fatal, we use ordinal numbers to access columns.
          Still this can be a sign of a tampered table, output an error
          to the error log.
        */
        report_error(0, "Incorrect definition of table %s.%s: "
                     "expected column '%s' at position %d, found '%s'.",
                     table->s->db.str, table->alias.c_ptr(),
                     field_def->name.str, i,
                     field->field_name);
      }
      field->sql_type(sql_type);
      /*
        Generally, if column types don't match, then something is
        wrong.

        However, we only compare column definitions up to the
        length of the original definition, since we consider the
        following definitions compatible:

        1. DATETIME and DATETIM
        2. INT(11) and INT(11
        3. SET('one', 'two') and SET('one', 'two', 'more')

        For SETs or ENUMs, if the same prefix is there it's OK to
        add more elements - they will get higher ordinal numbers and
        the new table definition is backward compatible with the
        original one.
       */
      if (strncmp(sql_type.c_ptr_safe(), field_def->type.str,
                  field_def->type.length - 1))
      {
        report_error(0, "Incorrect definition of table %s.%s: "
                     "expected column '%s' at position %d to have type "
                     "%s, found type %s.", table->s->db.str,
                     table->alias.c_ptr(),
                     field_def->name.str, i, field_def->type.str,
                     sql_type.c_ptr_safe());
        error= TRUE;
      }
      else if (field_def->cset.str && !field->has_charset())
      {
        report_error(0, "Incorrect definition of table %s.%s: "
                     "expected the type of column '%s' at position %d "
                     "to have character set '%s' but the type has no "
                     "character set.", table->s->db.str,
                     table->alias.c_ptr(),
                     field_def->name.str, i, field_def->cset.str);
        error= TRUE;
      }
      else if (field_def->cset.str &&
               strcmp(field->charset()->csname, field_def->cset.str))
      {
        report_error(0, "Incorrect definition of table %s.%s: "
                     "expected the type of column '%s' at position %d "
                     "to have character set '%s' but found "
                     "character set '%s'.", table->s->db.str,
                     table->alias.c_ptr(),
                     field_def->name.str, i, field_def->cset.str,
                     field->charset()->csname);
        error= TRUE;
      }
    }
    else
    {
      report_error(0, "Incorrect definition of table %s.%s: "
                   "expected column '%s' at position %d to have type %s "
                   " but the column is not found.",
                   table->s->db.str, table->alias.c_ptr(),
                   field_def->name.str, i, field_def->type.str);
      error= TRUE;
    }
  }
  }

  if (table_def->primary_key_parts)
  {
    if (table->s->primary_key == MAX_KEY)
    {
      report_error(0, "Incorrect definition of table %s.%s: "
                   "missing primary key.", table->s->db.str,
                   table->alias.c_ptr());
      error= TRUE;
    }
    else
    {
      KEY *pk= &table->s->key_info[table->s->primary_key];
      if (pk->user_defined_key_parts != table_def->primary_key_parts)
      {
        report_error(0, "Incorrect definition of table %s.%s: "
                     "Expected primary key to have %u columns, but instead "
                     "found %u columns.", table->s->db.str,
                     table->alias.c_ptr(), table_def->primary_key_parts,
                     pk->user_defined_key_parts);
        error= TRUE;
      }
      else
      {
        for (i= 0; i < pk->user_defined_key_parts; ++i)
        {
          if (table_def->primary_key_columns[i] + 1 != pk->key_part[i].fieldnr)
          {
            report_error(0, "Incorrect definition of table %s.%s: Expected "
                         "primary key part %u to refer to column %u, but "
                         "instead found column %u.", table->s->db.str,
                         table->alias.c_ptr(), i + 1,
                         table_def->primary_key_columns[i] + 1,
                         pk->key_part[i].fieldnr);
            error= TRUE;
          }
        }
      }
    }
  }

  if (! error)
    table->s->table_field_def_cache= table_def;

end:

  if (has_keys && !error && !table->key_info)
  {
    report_error(0, "Incorrect definition of table %s.%s: "
                 "indexes are missing",
                 table->s->db.str, table->alias.c_ptr());
    error= TRUE;
  }

  DBUG_RETURN(error);
}


void Table_check_intact_log_error::report_error(uint, const char *fmt, ...)
{
  va_list args;
  va_start(args, fmt);
  error_log_print(ERROR_LEVEL, fmt, args);
  va_end(args);
}


/**
  Traverse portion of wait-for graph which is reachable through edge
  represented by this flush ticket in search for deadlocks.

  @retval TRUE  A deadlock is found. A victim is remembered
                by the visitor.
  @retval FALSE Success, no deadlocks.
*/

bool Wait_for_flush::accept_visitor(MDL_wait_for_graph_visitor *gvisitor)
{
  return m_share->visit_subgraph(this, gvisitor);
}


uint Wait_for_flush::get_deadlock_weight() const
{
  return m_deadlock_weight;
}


/**
  Traverse portion of wait-for graph which is reachable through this
  table share in search for deadlocks.

  @param waiting_ticket  Ticket representing wait for this share.
  @param dvisitor        Deadlock detection visitor.

  @retval TRUE  A deadlock is found. A victim is remembered
                by the visitor.
  @retval FALSE No deadlocks, it's OK to begin wait.
*/

bool TABLE_SHARE::visit_subgraph(Wait_for_flush *wait_for_flush,
                                 MDL_wait_for_graph_visitor *gvisitor)
{
  TABLE *table;
  MDL_context *src_ctx= wait_for_flush->get_ctx();
  bool result= TRUE;

  /*
    To protect all_tables list from being concurrently modified
    while we are iterating through it we increment tdc.all_tables_refs.
    This does not introduce deadlocks in the deadlock detector
    because we won't try to acquire tdc.LOCK_table_share while
    holding a write-lock on MDL_lock::m_rwlock.
  */
  mysql_mutex_lock(&tdc->LOCK_table_share);
  tdc->all_tables_refs++;
  mysql_mutex_unlock(&tdc->LOCK_table_share);

  All_share_tables_list::Iterator tables_it(tdc->all_tables);

  /*
    In case of multiple searches running in parallel, avoid going
    over the same loop twice and shortcut the search.
    Do it after taking the lock to weed out unnecessary races.
  */
  if (src_ctx->m_wait.get_status() != MDL_wait::EMPTY)
  {
    result= FALSE;
    goto end;
  }

  if (gvisitor->enter_node(src_ctx))
    goto end;

  while ((table= tables_it++))
  {
    DBUG_ASSERT(table->in_use && tdc->flushed);
    if (gvisitor->inspect_edge(&table->in_use->mdl_context))
    {
      goto end_leave_node;
    }
  }

  tables_it.rewind();
  while ((table= tables_it++))
  {
    DBUG_ASSERT(table->in_use && tdc->flushed);
    if (table->in_use->mdl_context.visit_subgraph(gvisitor))
    {
      goto end_leave_node;
    }
  }

  result= FALSE;

end_leave_node:
  gvisitor->leave_node(src_ctx);

end:
  mysql_mutex_lock(&tdc->LOCK_table_share);
  if (!--tdc->all_tables_refs)
    mysql_cond_broadcast(&tdc->COND_release);
  mysql_mutex_unlock(&tdc->LOCK_table_share);

  return result;
}


/**
  Wait until the subject share is removed from the table
  definition cache and make sure it's destroyed.

  @param mdl_context     MDL context for thread which is going to wait.
  @param abstime         Timeout for waiting as absolute time value.
  @param deadlock_weight Weight of this wait for deadlock detector.

  @pre LOCK_table_share is locked, the share is marked for flush and
       this connection does not reference the share.
       LOCK_table_share will be unlocked temporarily during execution.

  It may happen that another FLUSH TABLES thread marked this share
  for flush, but didn't yet purge it from table definition cache.
  In this case we may start waiting for a table share that has no
  references (ref_count == 0). We do this with assumption that this
  another FLUSH TABLES thread is about to purge this share.

  @retval FALSE - Success.
  @retval TRUE  - Error (OOM, deadlock, timeout, etc...).
*/

bool TABLE_SHARE::wait_for_old_version(THD *thd, struct timespec *abstime,
                                       uint deadlock_weight)
{
  MDL_context *mdl_context= &thd->mdl_context;
  Wait_for_flush ticket(mdl_context, this, deadlock_weight);
  MDL_wait::enum_wait_status wait_status;

  mysql_mutex_assert_owner(&tdc->LOCK_table_share);
  DBUG_ASSERT(tdc->flushed);

  tdc->m_flush_tickets.push_front(&ticket);

  mdl_context->m_wait.reset_status();

  mysql_mutex_unlock(&tdc->LOCK_table_share);

  mdl_context->will_wait_for(&ticket);

  mdl_context->find_deadlock();

  wait_status= mdl_context->m_wait.timed_wait(thd, abstime, TRUE,
                                              &stage_waiting_for_table_flush);

  mdl_context->done_waiting_for();

  mysql_mutex_lock(&tdc->LOCK_table_share);
  tdc->m_flush_tickets.remove(&ticket);
  mysql_cond_broadcast(&tdc->COND_release);
  mysql_mutex_unlock(&tdc->LOCK_table_share);


  /*
    In cases when our wait was aborted by KILL statement,
    a deadlock or a timeout, the share might still be referenced,
    so we don't delete it. Note, that we can't determine this
    condition by checking wait_status alone, since, for example,
    a timeout can happen after all references to the table share
    were released, but before the share is removed from the
    cache and we receive the notification. This is why
    we first destroy the share, and then look at
    wait_status.
  */
  switch (wait_status)
  {
  case MDL_wait::GRANTED:
    return FALSE;
  case MDL_wait::VICTIM:
    my_error(ER_LOCK_DEADLOCK, MYF(0));
    return TRUE;
  case MDL_wait::TIMEOUT:
    my_error(ER_LOCK_WAIT_TIMEOUT, MYF(0));
    return TRUE;
  case MDL_wait::KILLED:
    return TRUE;
  default:
    DBUG_ASSERT(0);
    return TRUE;
  }
}


/**
  Initialize TABLE instance (newly created, or coming either from table
  cache or THD::temporary_tables list) and prepare it for further use
  during statement execution. Set the 'alias' attribute from the specified
  TABLE_LIST element. Remember the TABLE_LIST element in the
  TABLE::pos_in_table_list member.

  @param thd  Thread context.
  @param tl   TABLE_LIST element.
*/

void TABLE::init(THD *thd, TABLE_LIST *tl)
{
  DBUG_ASSERT(s->tmp_table != NO_TMP_TABLE || s->tdc->ref_count > 0);

  if (thd->lex->need_correct_ident())
    alias_name_used= my_strcasecmp(table_alias_charset,
                                   s->table_name.str,
                                   tl->alias);
  /* Fix alias if table name changes. */
  if (!alias.alloced_length() || strcmp(alias.c_ptr(), tl->alias))
    alias.copy(tl->alias, strlen(tl->alias), alias.charset());

  tablenr= thd->current_tablenr++;
  used_fields= 0;
  const_table= 0;
  null_row= 0;
  maybe_null= 0;
  force_index= 0;
  force_index_order= 0;
  force_index_group= 0;
  status= STATUS_NO_RECORD;
  insert_values= 0;
  fulltext_searched= 0;
  file->ft_handler= 0;
  reginfo.impossible_range= 0;
  created= TRUE;
  cond_selectivity= 1.0;
  cond_selectivity_sampling_explain= NULL;
  quick_condition_rows=0;
  initialize_quick_structures();
#ifdef HAVE_REPLICATION
  /* used in RBR Triggers */
  master_had_triggers= 0;
#endif

  /* Catch wrong handling of the auto_increment_field_not_null. */
  DBUG_ASSERT(!auto_increment_field_not_null);
  auto_increment_field_not_null= FALSE;

  pos_in_table_list= tl;

  clear_column_bitmaps();
  for (Field **f_ptr= field ; *f_ptr ; f_ptr++)
  {
    (*f_ptr)->next_equal_field= NULL;
    (*f_ptr)->cond_selectivity= 1.0;
  }

  DBUG_ASSERT(!file->keyread_enabled());

  restore_record(this, s->default_values);

  /* Tables may be reused in a sub statement. */
  DBUG_ASSERT(!file->extra(HA_EXTRA_IS_ATTACHED_CHILDREN));
}


/*
  Create Item_field for each column in the table.

  SYNPOSIS
    TABLE::fill_item_list()
      item_list          a pointer to an empty list used to store items

  DESCRIPTION
    Create Item_field object for each column in the table and
    initialize it with the corresponding Field. New items are
    created in the current THD memory root.

  RETURN VALUE
    0                    success
    1                    out of memory
*/

bool TABLE::fill_item_list(List<Item> *item_list) const
{
  /*
    All Item_field's created using a direct pointer to a field
    are fixed in Item_field constructor.
  */
  for (Field **ptr= field; *ptr; ptr++)
  {
    Item_field *item= new (in_use->mem_root) Item_field(in_use, *ptr);
    if (!item || item_list->push_back(item))
      return TRUE;
  }
  return FALSE;
}

/*
  Reset an existing list of Item_field items to point to the
  Fields of this table.

  SYNPOSIS
    TABLE::fill_item_list()
      item_list          a non-empty list with Item_fields

  DESCRIPTION
    This is a counterpart of fill_item_list used to redirect
    Item_fields to the fields of a newly created table.
    The caller must ensure that number of items in the item_list
    is the same as the number of columns in the table.
*/

void TABLE::reset_item_list(List<Item> *item_list) const
{
  List_iterator_fast<Item> it(*item_list);
  for (Field **ptr= field; *ptr; ptr++)
  {
    Item_field *item_field= (Item_field*) it++;
    DBUG_ASSERT(item_field != 0);
    item_field->reset_field(*ptr);
  }
}

/*
  calculate md5 of query

  SYNOPSIS
    TABLE_LIST::calc_md5()
    buffer	buffer for md5 writing
*/

void  TABLE_LIST::calc_md5(char *buffer)
{
  uchar digest[16];
  compute_md5_hash(digest, select_stmt.str,
                   select_stmt.length);
  sprintf((char *) buffer,
	    "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
	    digest[0], digest[1], digest[2], digest[3],
	    digest[4], digest[5], digest[6], digest[7],
	    digest[8], digest[9], digest[10], digest[11],
	    digest[12], digest[13], digest[14], digest[15]);
}


/**
  @brief
  Create field translation for mergeable derived table/view.

  @param thd  Thread handle

  @details
  Create field translation for mergeable derived table/view.

  @return FALSE ok.
  @return TRUE an error occur.
*/

bool TABLE_LIST::create_field_translation(THD *thd)
{
  Item *item;
  Field_translator *transl;
  SELECT_LEX *select= get_single_select();
  List_iterator_fast<Item> it(select->item_list);
  uint field_count= 0;
  Query_arena *arena, backup;
  bool res= FALSE;
  DBUG_ENTER("TABLE_LIST::create_field_translation");
  DBUG_PRINT("enter", ("Alias: '%s'  Unit: %p",
                      (alias ? alias : "<NULL>"),
                       get_unit()));

  if (thd->stmt_arena->is_conventional() ||
      thd->stmt_arena->is_stmt_prepare_or_first_sp_execute())
  {
    /* initialize lists */
    used_items.empty();
    persistent_used_items.empty();
  }
  else
  {
    /*
      Copy the list created by natural join procedure because the procedure
      will not be repeated.
    */
    used_items= persistent_used_items;
  }

  if (field_translation)
  {
    /*
      Update items in the field translation after view have been prepared.
      It's needed because some items in the select list, like IN subselects,
      might be substituted for optimized ones.
    */
    if (is_view() && get_unit()->prepared && !field_translation_updated)
    {
      while ((item= it++))
      {
        field_translation[field_count++].item= item;
      }
      field_translation_updated= TRUE;
    }

    DBUG_RETURN(FALSE);
  }

  arena= thd->activate_stmt_arena_if_needed(&backup);

  /* Create view fields translation table */

  if (!(transl=
        (Field_translator*)(thd->stmt_arena->
                            alloc(select->item_list.elements *
                                  sizeof(Field_translator)))))
  {
    res= TRUE;
    goto exit;
  }

  while ((item= it++))
  {
    DBUG_ASSERT(item->name && item->name[0]);
    transl[field_count].name= thd->strdup(item->name);
    transl[field_count++].item= item;
  }
  field_translation= transl;
  field_translation_end= transl + field_count;
  /* It's safe to cache this table for prepared statements */
  cacheable_table= 1;

exit:
  if (arena)
    thd->restore_active_arena(arena, &backup);

  DBUG_RETURN(res);
}


/**
  @brief
  Create field translation for mergeable derived table/view.

  @param thd  Thread handle

  @details
  Create field translation for mergeable derived table/view.

  @return FALSE ok.
  @return TRUE an error occur.
*/

bool TABLE_LIST::setup_underlying(THD *thd)
{
  DBUG_ENTER("TABLE_LIST::setup_underlying");

  if (!view || (!field_translation && merge_underlying_list))
  {
    SELECT_LEX *select= get_single_select();

    if (create_field_translation(thd))
      DBUG_RETURN(TRUE);

    /* full text function moving to current select */
    if (select->ftfunc_list->elements)
    {
      Item_func_match *ifm;
      SELECT_LEX *current_select= thd->lex->current_select;
      List_iterator_fast<Item_func_match>
        li(*(select_lex->ftfunc_list));
      while ((ifm= li++))
        current_select->ftfunc_list->push_front(ifm);
    }
  }
  DBUG_RETURN(FALSE);
}


/*
   Prepare where expression of derived table/view

  SYNOPSIS
    TABLE_LIST::prep_where()
    thd             - thread handler
    conds           - condition of this JOIN
    no_where_clause - do not build WHERE or ON outer qwery do not need it
                      (it is INSERT), we do not need conds if this flag is set

  NOTE: have to be called befor CHECK OPTION preparation, because it makes
  fix_fields for view WHERE clause

  RETURN
    FALSE - OK
    TRUE  - error
*/

bool TABLE_LIST::prep_where(THD *thd, Item **conds,
                               bool no_where_clause)
{
  DBUG_ENTER("TABLE_LIST::prep_where");
  bool res= FALSE;

  for (TABLE_LIST *tbl= merge_underlying_list; tbl; tbl= tbl->next_local)
  {
    if (tbl->is_view_or_derived() &&
        tbl->prep_where(thd, conds, no_where_clause))
    {
      DBUG_RETURN(TRUE);
    }
  }

  if (where)
  {
    if (where->fixed)
      where->update_used_tables();
    if (!where->fixed && where->fix_fields(thd, &where))
    {
      DBUG_RETURN(TRUE);
    }

    /*
      check that it is not VIEW in which we insert with INSERT SELECT
      (in this case we can't add view WHERE condition to main SELECT_LEX)
    */
    if (!no_where_clause && !where_processed)
    {
      TABLE_LIST *tbl= this;
      Query_arena *arena= thd->stmt_arena, backup;
      arena= thd->activate_stmt_arena_if_needed(&backup);  // For easier test

      /* Go up to join tree and try to find left join */
      for (; tbl; tbl= tbl->embedding)
      {
        if (tbl->outer_join)
        {
          /*
            Store WHERE condition to ON expression for outer join, because
            we can't use WHERE to correctly execute left joins on VIEWs and
            this expression will not be moved to WHERE condition (i.e. will
            be clean correctly for PS/SP)
          */
          tbl->on_expr= and_conds(thd, tbl->on_expr,
                                  where->copy_andor_structure(thd));
          break;
        }
      }
      if (tbl == 0)
      {
        if (*conds && !(*conds)->fixed)
          res= (*conds)->fix_fields(thd, conds);
        if (!res)
          *conds= and_conds(thd, *conds, where->copy_andor_structure(thd));
        if (*conds && !(*conds)->fixed && !res)
          res= (*conds)->fix_fields(thd, conds);
      }
      if (arena)
        thd->restore_active_arena(arena, &backup);
      where_processed= TRUE;
    }
  }

  DBUG_RETURN(res);
}

/**
  Check that table/view is updatable and if it has single
  underlying tables/views it is also updatable

  @return Result of the check.
*/

bool TABLE_LIST::single_table_updatable()
{
  if (!updatable)
    return false;
  if (view && view->select_lex.table_list.elements == 1)
  {
    /*
      We need to check deeply only single table views. Multi-table views
      will be turned to multi-table updates and then checked by leaf tables
    */
    return (((TABLE_LIST *)view->select_lex.table_list.first)->
            single_table_updatable());
  }
  return true;
}


/*
  Merge ON expressions for a view

  SYNOPSIS
    merge_on_conds()
    thd             thread handle
    table           table for the VIEW
    is_cascaded     TRUE <=> merge ON expressions from underlying views

  DESCRIPTION
    This function returns the result of ANDing the ON expressions
    of the given view and all underlying views. The ON expressions
    of the underlying views are added only if is_cascaded is TRUE.

  RETURN
    Pointer to the built expression if there is any.
    Otherwise and in the case of a failure NULL is returned.
*/

static Item *
merge_on_conds(THD *thd, TABLE_LIST *table, bool is_cascaded)
{
  DBUG_ENTER("merge_on_conds");

  Item *cond= NULL;
  DBUG_PRINT("info", ("alias: %s", table->alias));
  if (table->on_expr)
    cond= table->on_expr->copy_andor_structure(thd);
  if (!table->view)
    DBUG_RETURN(cond);
  for (TABLE_LIST *tbl= (TABLE_LIST*)table->view->select_lex.table_list.first;
       tbl;
       tbl= tbl->next_local)
  {
    if (tbl->view && !is_cascaded)
      continue;
    cond= and_conds(thd, cond, merge_on_conds(thd, tbl, is_cascaded));
  }
  DBUG_RETURN(cond);
}


/*
  Prepare check option expression of table

  SYNOPSIS
    TABLE_LIST::prep_check_option()
    thd             - thread handler
    check_opt_type  - WITH CHECK OPTION type (VIEW_CHECK_NONE,
                      VIEW_CHECK_LOCAL, VIEW_CHECK_CASCADED)
                      we use this parameter instead of direct check of
                      effective_with_check to change type of underlying
                      views to VIEW_CHECK_CASCADED if outer view have
                      such option and prevent processing of underlying
                      view check options if outer view have just
                      VIEW_CHECK_LOCAL option.

  NOTE
    This method builds check option condition to use it later on
    every call (usual execution or every SP/PS call).
    This method have to be called after WHERE preparation
    (TABLE_LIST::prep_where)

  RETURN
    FALSE - OK
    TRUE  - error
*/

bool TABLE_LIST::prep_check_option(THD *thd, uint8 check_opt_type)
{
  DBUG_ENTER("TABLE_LIST::prep_check_option");
  bool is_cascaded= check_opt_type == VIEW_CHECK_CASCADED;
  TABLE_LIST *merge_underlying_list= view->select_lex.get_table_list();
  for (TABLE_LIST *tbl= merge_underlying_list; tbl; tbl= tbl->next_local)
  {
    /* see comment of check_opt_type parameter */
    if (tbl->view && tbl->prep_check_option(thd, (is_cascaded ?
                                                  VIEW_CHECK_CASCADED :
                                                  VIEW_CHECK_NONE)))
      DBUG_RETURN(TRUE);
  }

  if (check_opt_type && !check_option_processed)
  {
    Query_arena *arena= thd->stmt_arena, backup;
    arena= thd->activate_stmt_arena_if_needed(&backup);  // For easier test

    if (where)
    {
      check_option= where->copy_andor_structure(thd);
    }
    if (is_cascaded)
    {
      for (TABLE_LIST *tbl= merge_underlying_list; tbl; tbl= tbl->next_local)
      {
        if (tbl->check_option)
          check_option= and_conds(thd, check_option, tbl->check_option);
      }
    }
    check_option= and_conds(thd, check_option,
                            merge_on_conds(thd, this, is_cascaded));

    if (arena)
      thd->restore_active_arena(arena, &backup);
    check_option_processed= TRUE;

  }

  if (check_option)
  {
    const char *save_where= thd->where;
    thd->where= "check option";
    if ((!check_option->fixed &&
         check_option->fix_fields(thd, &check_option)) ||
        check_option->check_cols(1))
    {
      DBUG_RETURN(TRUE);
    }
    thd->where= save_where;
  }
  DBUG_RETURN(FALSE);
}


/**
  Hide errors which show view underlying table information. 
  There are currently two mechanisms at work that handle errors for views,
  this one and a more general mechanism based on an Internal_error_handler,
  see Show_create_error_handler. The latter handles errors encountered during
  execution of SHOW CREATE VIEW, while the mechanism using this method is
  handles SELECT from views. The two methods should not clash.

  @param[in,out]  thd     thread handler

  @pre This method can be called only if there is an error.
*/

void TABLE_LIST::hide_view_error(THD *thd)
{
  if ((thd->killed && !thd->is_error())|| thd->get_internal_handler())
    return;
  /* Hide "Unknown column" or "Unknown function" error */
  DBUG_ASSERT(thd->is_error());
  switch (thd->get_stmt_da()->sql_errno()) {
    case ER_BAD_FIELD_ERROR:
    case ER_SP_DOES_NOT_EXIST:
    case ER_FUNC_INEXISTENT_NAME_COLLISION:
    case ER_PROCACCESS_DENIED_ERROR:
    case ER_COLUMNACCESS_DENIED_ERROR:
    case ER_TABLEACCESS_DENIED_ERROR:
    case ER_TABLE_NOT_LOCKED:
    case ER_NO_SUCH_TABLE:
    {
      TABLE_LIST *top= top_table();
      thd->clear_error();
      my_error(ER_VIEW_INVALID, MYF(0),
               top->view_db.str, top->view_name.str);
      break;
    }

    case ER_NO_DEFAULT_FOR_FIELD:
    {
      TABLE_LIST *top= top_table();
      thd->clear_error();
      // TODO: make correct error message
      my_error(ER_NO_DEFAULT_FOR_VIEW_FIELD, MYF(0),
               top->view_db.str, top->view_name.str);
      break;
    }
  }
}


/*
  Find underlying base tables (TABLE_LIST) which represent given
  table_to_find (TABLE)

  SYNOPSIS
    TABLE_LIST::find_underlying_table()
    table_to_find table to find

  RETURN
    0  table is not found
    found table reference
*/

TABLE_LIST *TABLE_LIST::find_underlying_table(TABLE *table_to_find)
{
  /* is this real table and table which we are looking for? */
  if (table == table_to_find && view == 0)
    return this;
  if (!view)
    return 0;

  for (TABLE_LIST *tbl= view->select_lex.get_table_list();
       tbl;
       tbl= tbl->next_local)
  {
    TABLE_LIST *result;
    if ((result= tbl->find_underlying_table(table_to_find)))
      return result;
  }
  return 0;
}

/*
  cleanup items belonged to view fields translation table

  SYNOPSIS
    TABLE_LIST::cleanup_items()
*/

void TABLE_LIST::cleanup_items()
{
  if (!field_translation)
    return;

  for (Field_translator *transl= field_translation;
       transl < field_translation_end;
       transl++)
    transl->item->walk(&Item::cleanup_processor, 0, 0);
}


/*
  check CHECK OPTION condition both for view and underlying table

  SYNOPSIS
    TABLE_LIST::view_check_option()
    ignore_failure ignore check option fail

  RETURN
    VIEW_CHECK_OK     OK
    VIEW_CHECK_ERROR  FAILED
    VIEW_CHECK_SKIP   FAILED, but continue
*/


int TABLE_LIST::view_check_option(THD *thd, bool ignore_failure)
{
  if (check_option)
  {
    /* VIEW's CHECK OPTION CLAUSE */
    Counting_error_handler ceh;
    thd->push_internal_handler(&ceh);
    bool res= check_option->val_int() == 0;
    thd->pop_internal_handler();
    if (ceh.errors)
      return(VIEW_CHECK_ERROR);
    if (res)
    {
      TABLE_LIST *main_view= top_table();
      const char *name_db= (main_view->view ? main_view->view_db.str :
                            main_view->db);
      const char *name_table= (main_view->view ? main_view->view_name.str :
                               main_view->table_name);
      my_error(ER_VIEW_CHECK_FAILED, MYF(ignore_failure ? ME_JUST_WARNING : 0),
               name_db, name_table);
      return ignore_failure ? VIEW_CHECK_SKIP : VIEW_CHECK_ERROR;
    }
  }
  return table->verify_constraints(ignore_failure);
}


int TABLE::verify_constraints(bool ignore_failure)
{
  /*
    We have to check is_error() first as we are checking it for each
    constraint to catch fatal warnings.
  */
  if (in_use->is_error())
    return (VIEW_CHECK_ERROR);

  /* go trough check option clauses for fields and table */
  if (check_constraints &&
      !(in_use->variables.option_bits & OPTION_NO_CHECK_CONSTRAINT_CHECKS))
  {
    for (Virtual_column_info **chk= check_constraints ; *chk ; chk++)
    {
      /*
        yes! NULL is ok.
        see 4.23.3.4 Table check constraints, part 2, SQL:2016
      */
      if (((*chk)->expr->val_int() == 0 && !(*chk)->expr->null_value) ||
          in_use->is_error())
      {
        StringBuffer<MAX_FIELD_WIDTH> field_error(system_charset_info);
        enum_vcol_info_type vcol_type= (*chk)->get_vcol_type();
        DBUG_ASSERT(vcol_type == VCOL_CHECK_TABLE ||
                    vcol_type == VCOL_CHECK_FIELD);
        if (vcol_type == VCOL_CHECK_FIELD)
        {
          field_error.append(s->table_name.str);
          field_error.append(".");
        }
        field_error.append((*chk)->name.str);
        my_error(ER_CONSTRAINT_FAILED,
                 MYF(ignore_failure ? ME_JUST_WARNING : 0), field_error.c_ptr(),
                 s->db.str, s->table_name.str);
        return ignore_failure ? VIEW_CHECK_SKIP : VIEW_CHECK_ERROR;
      }
    }
  }
  /*
    We have to check in_use() as checking constraints may have generated
    warnings that should be treated as errors
  */
  return(!in_use->is_error() ? VIEW_CHECK_OK : VIEW_CHECK_ERROR);
}


/*
  Find table in underlying tables by mask and check that only this
  table belong to given mask

  SYNOPSIS
    TABLE_LIST::check_single_table()
    table_arg	reference on variable where to store found table
		(should be 0 on call, to find table, or point to table for
		unique test)
    map         bit mask of tables
    view_arg    view for which we are looking table

  RETURN
    FALSE table not found or found only one
    TRUE  found several tables
*/

bool TABLE_LIST::check_single_table(TABLE_LIST **table_arg,
                                       table_map map,
                                       TABLE_LIST *view_arg)
{
  if (!select_lex)
    return FALSE;
  DBUG_ASSERT(is_merged_derived());
  for (TABLE_LIST *tbl= get_single_select()->get_table_list();
       tbl;
       tbl= tbl->next_local)
  {
    /*
      Merged view has also temporary table attached (in 5.2 if it has table
      then it was real table), so we have filter such temporary tables out
      by checking that it is not merged view
    */
    if (tbl->table &&
        !(tbl->is_view() &&
          tbl->is_merged_derived()))
    {
      if (tbl->table->map & map)
      {
	if (*table_arg)
	  return TRUE;
        *table_arg= tbl;
        tbl->check_option= view_arg->check_option;
      }
    }
    else if (tbl->check_single_table(table_arg, map, view_arg))
      return TRUE;
  }
  return FALSE;
}


/*
  Set insert_values buffer

  SYNOPSIS
    set_insert_values()
    mem_root   memory pool for allocating

  RETURN
    FALSE - OK
    TRUE  - out of memory
*/

bool TABLE_LIST::set_insert_values(MEM_ROOT *mem_root)
{
  DBUG_ENTER("set_insert_values");
  if (table)
  {
    DBUG_PRINT("info", ("setting insert_value for table"));
    if (!table->insert_values &&
        !(table->insert_values= (uchar *)alloc_root(mem_root,
                                                   table->s->rec_buff_length)))
      DBUG_RETURN(TRUE);
  }
  else
  {
    DBUG_PRINT("info", ("setting insert_value for view"));
    DBUG_ASSERT(is_view_or_derived() && is_merged_derived());
    for (TABLE_LIST *tbl= (TABLE_LIST*)view->select_lex.table_list.first;
         tbl;
         tbl= tbl->next_local)
      if (tbl->set_insert_values(mem_root))
        DBUG_RETURN(TRUE);
  }
  DBUG_RETURN(FALSE);
}


/*
  Test if this is a leaf with respect to name resolution.

  SYNOPSIS
    TABLE_LIST::is_leaf_for_name_resolution()

  DESCRIPTION
    A table reference is a leaf with respect to name resolution if
    it is either a leaf node in a nested join tree (table, view,
    schema table, subquery), or an inner node that represents a
    NATURAL/USING join, or a nested join with materialized join
    columns.

  RETURN
    TRUE if a leaf, FALSE otherwise.
*/
bool TABLE_LIST::is_leaf_for_name_resolution()
{
  return (is_merged_derived() || is_natural_join || is_join_columns_complete ||
          !nested_join);
}


/*
  Retrieve the first (left-most) leaf in a nested join tree with
  respect to name resolution.

  SYNOPSIS
    TABLE_LIST::first_leaf_for_name_resolution()

  DESCRIPTION
    Given that 'this' is a nested table reference, recursively walk
    down the left-most children of 'this' until we reach a leaf
    table reference with respect to name resolution.

  IMPLEMENTATION
    The left-most child of a nested table reference is the last element
    in the list of children because the children are inserted in
    reverse order.

  RETURN
    If 'this' is a nested table reference - the left-most child of
      the tree rooted in 'this',
    else return 'this'
*/

TABLE_LIST *TABLE_LIST::first_leaf_for_name_resolution()
{
  TABLE_LIST *UNINIT_VAR(cur_table_ref);
  NESTED_JOIN *cur_nested_join;

  if (is_leaf_for_name_resolution())
    return this;
  DBUG_ASSERT(nested_join);

  for (cur_nested_join= nested_join;
       cur_nested_join;
       cur_nested_join= cur_table_ref->nested_join)
  {
    List_iterator_fast<TABLE_LIST> it(cur_nested_join->join_list);
    cur_table_ref= it++;
    /*
      If the current nested join is a RIGHT JOIN, the operands in
      'join_list' are in reverse order, thus the first operand is
      already at the front of the list. Otherwise the first operand
      is in the end of the list of join operands.
    */
    if (!(cur_table_ref->outer_join & JOIN_TYPE_RIGHT))
    {
      TABLE_LIST *next;
      while ((next= it++))
        cur_table_ref= next;
    }
    if (cur_table_ref->is_leaf_for_name_resolution())
      break;
  }
  return cur_table_ref;
}


/*
  Retrieve the last (right-most) leaf in a nested join tree with
  respect to name resolution.

  SYNOPSIS
    TABLE_LIST::last_leaf_for_name_resolution()

  DESCRIPTION
    Given that 'this' is a nested table reference, recursively walk
    down the right-most children of 'this' until we reach a leaf
    table reference with respect to name resolution.

  IMPLEMENTATION
    The right-most child of a nested table reference is the first
    element in the list of children because the children are inserted
    in reverse order.

  RETURN
    - If 'this' is a nested table reference - the right-most child of
      the tree rooted in 'this',
    - else - 'this'
*/

TABLE_LIST *TABLE_LIST::last_leaf_for_name_resolution()
{
  TABLE_LIST *cur_table_ref= this;
  NESTED_JOIN *cur_nested_join;

  if (is_leaf_for_name_resolution())
    return this;
  DBUG_ASSERT(nested_join);

  for (cur_nested_join= nested_join;
       cur_nested_join;
       cur_nested_join= cur_table_ref->nested_join)
  {
    cur_table_ref= cur_nested_join->join_list.head();
    /*
      If the current nested is a RIGHT JOIN, the operands in
      'join_list' are in reverse order, thus the last operand is in the
      end of the list.
    */
    if ((cur_table_ref->outer_join & JOIN_TYPE_RIGHT))
    {
      List_iterator_fast<TABLE_LIST> it(cur_nested_join->join_list);
      TABLE_LIST *next;
      cur_table_ref= it++;
      while ((next= it++))
        cur_table_ref= next;
    }
    if (cur_table_ref->is_leaf_for_name_resolution())
      break;
  }
  return cur_table_ref;
}


/*
  Register access mode which we need for underlying tables

  SYNOPSIS
    register_want_access()
    want_access          Acess which we require
*/

void TABLE_LIST::register_want_access(ulong want_access)
{
  /* Remove SHOW_VIEW_ACL, because it will be checked during making view */
  want_access&= ~SHOW_VIEW_ACL;
  if (belong_to_view)
  {
    grant.want_privilege= want_access;
    if (table)
      table->grant.want_privilege= want_access;
  }
  if (!view)
    return;
  for (TABLE_LIST *tbl= view->select_lex.get_table_list();
       tbl;
       tbl= tbl->next_local)
    tbl->register_want_access(want_access);
}


/*
  Load security context information for this view

  SYNOPSIS
    TABLE_LIST::prepare_view_security_context()
    thd                  [in] thread handler

  RETURN
    FALSE  OK
    TRUE   Error
*/

#ifndef NO_EMBEDDED_ACCESS_CHECKS
bool TABLE_LIST::prepare_view_security_context(THD *thd)
{
  DBUG_ENTER("TABLE_LIST::prepare_view_security_context");
  DBUG_PRINT("enter", ("table: %s", alias));

  DBUG_ASSERT(!prelocking_placeholder && view);
  if (view_suid)
  {
    DBUG_PRINT("info", ("This table is suid view => load contest"));
    DBUG_ASSERT(view && view_sctx);
    if (acl_getroot(view_sctx, definer.user.str, definer.host.str,
                                definer.host.str, thd->db))
    {
      if ((thd->lex->sql_command == SQLCOM_SHOW_CREATE) ||
          (thd->lex->sql_command == SQLCOM_SHOW_FIELDS))
      {
        push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE, 
                            ER_NO_SUCH_USER, 
                            ER_THD(thd, ER_NO_SUCH_USER),
                            definer.user.str, definer.host.str);
      }
      else
      {
        if (thd->security_ctx->master_access & SUPER_ACL)
        {
          my_error(ER_NO_SUCH_USER, MYF(0), definer.user.str, definer.host.str);

        }
        else
        {
          if (thd->password == 2)
            my_error(ER_ACCESS_DENIED_NO_PASSWORD_ERROR, MYF(0),
                     thd->security_ctx->priv_user,
                     thd->security_ctx->priv_host);
          else
            my_error(ER_ACCESS_DENIED_ERROR, MYF(0),
                     thd->security_ctx->priv_user,
                     thd->security_ctx->priv_host,
                     (thd->password ?  ER_THD(thd, ER_YES) :
                      ER_THD(thd, ER_NO)));
        }
        DBUG_RETURN(TRUE);
      }
    }
  }
  DBUG_RETURN(FALSE);

}
#endif


/*
  Find security context of current view

  SYNOPSIS
    TABLE_LIST::find_view_security_context()
    thd                  [in] thread handler

*/

#ifndef NO_EMBEDDED_ACCESS_CHECKS
Security_context *TABLE_LIST::find_view_security_context(THD *thd)
{
  Security_context *sctx;
  TABLE_LIST *upper_view= this;
  DBUG_ENTER("TABLE_LIST::find_view_security_context");

  DBUG_ASSERT(view);
  while (upper_view && !upper_view->view_suid)
  {
    DBUG_ASSERT(!upper_view->prelocking_placeholder);
    upper_view= upper_view->referencing_view;
  }
  if (upper_view)
  {
    DBUG_PRINT("info", ("Securety context of view %s will be used",
                        upper_view->alias));
    sctx= upper_view->view_sctx;
    DBUG_ASSERT(sctx);
  }
  else
  {
    DBUG_PRINT("info", ("Current global context will be used"));
    sctx= thd->security_ctx;
  }
  DBUG_RETURN(sctx);
}
#endif


/*
  Prepare security context and load underlying tables priveleges for view

  SYNOPSIS
    TABLE_LIST::prepare_security()
    thd                  [in] thread handler

  RETURN
    FALSE  OK
    TRUE   Error
*/

bool TABLE_LIST::prepare_security(THD *thd)
{
  List_iterator_fast<TABLE_LIST> tb(*view_tables);
  TABLE_LIST *tbl;
  DBUG_ENTER("TABLE_LIST::prepare_security");
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  Security_context *save_security_ctx= thd->security_ctx;

  DBUG_ASSERT(!prelocking_placeholder);
  if (prepare_view_security_context(thd))
    DBUG_RETURN(TRUE);
  thd->security_ctx= find_view_security_context(thd);
  while ((tbl= tb++))
  {
    DBUG_ASSERT(tbl->referencing_view);
    char *local_db, *local_table_name;
    if (tbl->view)
    {
      local_db= tbl->view_db.str;
      local_table_name= tbl->view_name.str;
    }
    else
    {
      local_db= tbl->db;
      local_table_name= tbl->table_name;
    }
    fill_effective_table_privileges(thd, &tbl->grant, local_db,
                                    local_table_name);
    if (tbl->table)
      tbl->table->grant= grant;
  }
  thd->security_ctx= save_security_ctx;
#else
  while ((tbl= tb++))
    tbl->grant.privilege= ~NO_ACCESS;
#endif
  DBUG_RETURN(FALSE);
}

#ifndef DBUG_OFF
void TABLE_LIST::set_check_merged()
{
  DBUG_ASSERT(derived);
  /*
    It is not simple to check all, but at least this should be checked:
    this select is not excluded or the exclusion came from above.
  */
  DBUG_ASSERT(derived->is_excluded() ||
              !derived->first_select()->exclude_from_table_unique_test ||
              derived->outer_select()->
              exclude_from_table_unique_test);
}
#endif

void TABLE_LIST::set_check_materialized()
{
  DBUG_ENTER("TABLE_LIST::set_check_materialized");
  SELECT_LEX_UNIT *derived= this->derived;
  if (view)
    derived= &view->unit;
  DBUG_ASSERT(derived);
  DBUG_ASSERT(!derived->is_excluded());
  if (!derived->first_select()->exclude_from_table_unique_test)
    derived->set_unique_exclude();
  else
  {
    /*
      The subtree should be already excluded
    */
    DBUG_ASSERT(!derived->first_select()->first_inner_unit() ||
                derived->first_select()->first_inner_unit()->first_select()->
                exclude_from_table_unique_test);
  }
  DBUG_VOID_RETURN;
}

TABLE *TABLE_LIST::get_real_join_table()
{
  TABLE_LIST *tbl= this;
  while (tbl->table == NULL || tbl->table->reginfo.join_tab == NULL)
  {
    if ((tbl->view == NULL && tbl->derived == NULL) ||
        tbl->is_materialized_derived())
      break;
    /* we do not support merging of union yet */
    DBUG_ASSERT(tbl->view == NULL ||
               tbl->view->select_lex.next_select() == NULL);
    DBUG_ASSERT(tbl->derived == NULL ||
               tbl->derived->first_select()->next_select() == NULL);

    {
      List_iterator_fast<TABLE_LIST>
        ti(tbl->view != NULL ?
           tbl->view->select_lex.top_join_list :
           tbl->derived->first_select()->top_join_list);
      for (;;)
      {
        tbl= NULL;
        /*
          Find left table in outer join on this level
          (the list is reverted).
        */
        for (TABLE_LIST *t= ti++; t; t= ti++)
          tbl= t;
        if (!tbl)
          return NULL; // view/derived with no tables
        if (!tbl->nested_join)
          break;
        /* go deeper if we've found nested join */
        ti= tbl->nested_join->join_list;
      }
    }
  }

  return tbl->table;
}


Natural_join_column::Natural_join_column(Field_translator *field_param,
                                         TABLE_LIST *tab)
{
  DBUG_ASSERT(tab->field_translation);
  view_field= field_param;
  table_field= NULL;
  table_ref= tab;
  is_common= FALSE;
}


Natural_join_column::Natural_join_column(Item_field *field_param,
                                         TABLE_LIST *tab)
{
  DBUG_ASSERT(tab->table == field_param->field->table);
  table_field= field_param;
  view_field= NULL;
  table_ref= tab;
  is_common= FALSE;
}


const char *Natural_join_column::name()
{
  if (view_field)
  {
    DBUG_ASSERT(table_field == NULL);
    return view_field->name;
  }

  return table_field->field_name;
}


Item *Natural_join_column::create_item(THD *thd)
{
  if (view_field)
  {
    DBUG_ASSERT(table_field == NULL);
    return create_view_field(thd, table_ref, &view_field->item,
                             view_field->name);
  }
  return table_field;
}


Field *Natural_join_column::field()
{
  if (view_field)
  {
    DBUG_ASSERT(table_field == NULL);
    return NULL;
  }
  return table_field->field;
}


const char *Natural_join_column::table_name()
{
  DBUG_ASSERT(table_ref);
  return table_ref->alias;
}


const char *Natural_join_column::db_name()
{
  if (view_field)
    return table_ref->view_db.str;

  /*
    Test that TABLE_LIST::db is the same as TABLE_SHARE::db to
    ensure consistency. An exception are I_S schema tables, which
    are inconsistent in this respect.
  */
  DBUG_ASSERT(!strcmp(table_ref->db,
                      table_ref->table->s->db.str) ||
              (table_ref->schema_table &&
               is_infoschema_db(table_ref->table->s->db.str,
                                table_ref->table->s->db.length)) ||
               table_ref->is_materialized_derived());
  return table_ref->db;
}


GRANT_INFO *Natural_join_column::grant()
{
/*  if (view_field)
    return &(table_ref->grant);
  return &(table_ref->table->grant);*/
  /*
    Have to check algorithm because merged derived also has
    field_translation.
  */
//if (table_ref->effective_algorithm == DTYPE_ALGORITHM_MERGE)
  if (table_ref->is_merged_derived())
    return &(table_ref->grant);
  return &(table_ref->table->grant);
}


void Field_iterator_view::set(TABLE_LIST *table)
{
  DBUG_ASSERT(table->field_translation);
  view= table;
  ptr= table->field_translation;
  array_end= table->field_translation_end;
}


const char *Field_iterator_table::name()
{
  return (*ptr)->field_name;
}


Item *Field_iterator_table::create_item(THD *thd)
{
  SELECT_LEX *select= thd->lex->current_select;

  Item_field *item= new (thd->mem_root) Item_field(thd, &select->context, *ptr);
  if (item && thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
      !thd->lex->in_sum_func && select->cur_pos_in_select_list != UNDEF_POS &&
      select->join)
  {
    select->join->non_agg_fields.push_back(item);
    item->marker= select->cur_pos_in_select_list;
    select->set_non_agg_field_used(true);
  }
  return item;
}


const char *Field_iterator_view::name()
{
  return ptr->name;
}


Item *Field_iterator_view::create_item(THD *thd)
{
  return create_view_field(thd, view, &ptr->item, ptr->name);
}

Item *create_view_field(THD *thd, TABLE_LIST *view, Item **field_ref,
                        const char *name)
{
  bool save_wrapper= thd->lex->select_lex.no_wrap_view_item;
  Item *field= *field_ref;
  DBUG_ENTER("create_view_field");

  if (view->schema_table_reformed)
  {
    /*
      Translation table items are always Item_fields and already fixed
      ('mysql_schema_table' function). So we can return directly the
      field. This case happens only for 'show & where' commands.
    */
    DBUG_ASSERT(field && field->fixed);
    DBUG_RETURN(field);
  }

  DBUG_ASSERT(field);
  thd->lex->current_select->no_wrap_view_item= TRUE;
  if (!field->fixed)
  {
    if (field->fix_fields(thd, field_ref))
    {
      thd->lex->current_select->no_wrap_view_item= save_wrapper;
      DBUG_RETURN(0);
    }
    field= *field_ref;
  }
  thd->lex->current_select->no_wrap_view_item= save_wrapper;
  if (save_wrapper)
  {
    DBUG_RETURN(field);
  }
  Name_resolution_context *context= view->view ? &view->view->select_lex.context :
                                    &thd->lex->select_lex.context;
  Item *item= (new (thd->mem_root)
               Item_direct_view_ref(thd, context, field_ref, view->alias,
                                    name, view));
  if (!item)
    return NULL;
  /*
    Force creation of nullable item for the result tmp table for outer joined
    views/derived tables.
  */
  if (view->table && view->table->maybe_null)
    item->maybe_null= TRUE;
  /* Save item in case we will need to fall back to materialization. */
  view->used_items.push_front(item, thd->mem_root);
  /*
    If we create this reference on persistent memory then it should be
    present in persistent list
  */
  if (thd->mem_root == thd->stmt_arena->mem_root)
    view->persistent_used_items.push_front(item, thd->mem_root);
  DBUG_RETURN(item);
}


void Field_iterator_natural_join::set(TABLE_LIST *table_ref)
{
  DBUG_ASSERT(table_ref->join_columns);
  column_ref_it.init(*(table_ref->join_columns));
  cur_column_ref= column_ref_it++;
}


void Field_iterator_natural_join::next()
{
  cur_column_ref= column_ref_it++;
  DBUG_ASSERT(!cur_column_ref || ! cur_column_ref->table_field ||
              cur_column_ref->table_ref->table ==
              cur_column_ref->table_field->field->table);
}


void Field_iterator_table_ref::set_field_iterator()
{
  DBUG_ENTER("Field_iterator_table_ref::set_field_iterator");
  /*
    If the table reference we are iterating over is a natural join, or it is
    an operand of a natural join, and TABLE_LIST::join_columns contains all
    the columns of the join operand, then we pick the columns from
    TABLE_LIST::join_columns, instead of the  orginial container of the
    columns of the join operator.
  */
  if (table_ref->is_join_columns_complete)
  {
    /* Necesary, but insufficient conditions. */
    DBUG_ASSERT(table_ref->is_natural_join ||
                table_ref->nested_join ||
                (table_ref->join_columns &&
                 /* This is a merge view. */
                 ((table_ref->field_translation &&
                   table_ref->join_columns->elements ==
                   (ulong)(table_ref->field_translation_end -
                           table_ref->field_translation)) ||
                  /* This is stored table or a tmptable view. */
                  (!table_ref->field_translation &&
                   table_ref->join_columns->elements ==
                   table_ref->table->s->fields))));
    field_it= &natural_join_it;
    DBUG_PRINT("info",("field_it for '%s' is Field_iterator_natural_join",
                       table_ref->alias));
  }
  /* This is a merge view, so use field_translation. */
  else if (table_ref->field_translation)
  {
    DBUG_ASSERT(table_ref->is_merged_derived());
    field_it= &view_field_it;
    DBUG_PRINT("info", ("field_it for '%s' is Field_iterator_view",
                        table_ref->alias));
  }
  /* This is a base table or stored view. */
  else
  {
    DBUG_ASSERT(table_ref->table || table_ref->view);
    field_it= &table_field_it;
    DBUG_PRINT("info", ("field_it for '%s' is Field_iterator_table",
                        table_ref->alias));
  }
  field_it->set(table_ref);
  DBUG_VOID_RETURN;
}


void Field_iterator_table_ref::set(TABLE_LIST *table)
{
  DBUG_ASSERT(table);
  first_leaf= table->first_leaf_for_name_resolution();
  last_leaf=  table->last_leaf_for_name_resolution();
  DBUG_ASSERT(first_leaf && last_leaf);
  table_ref= first_leaf;
  set_field_iterator();
}


void Field_iterator_table_ref::next()
{
  /* Move to the next field in the current table reference. */
  field_it->next();
  /*
    If all fields of the current table reference are exhausted, move to
    the next leaf table reference.
  */
  if (field_it->end_of_fields() && table_ref != last_leaf)
  {
    table_ref= table_ref->next_name_resolution_table;
    DBUG_ASSERT(table_ref);
    set_field_iterator();
  }
}


const char *Field_iterator_table_ref::get_table_name()
{
  if (table_ref->view)
    return table_ref->view_name.str;
  if (table_ref->is_derived())
    return table_ref->table->s->table_name.str;
  else if (table_ref->is_natural_join)
    return natural_join_it.column_ref()->table_name();

  DBUG_ASSERT(!strcmp(table_ref->table_name,
                      table_ref->table->s->table_name.str) ||
              table_ref->schema_table);
  return table_ref->table_name;
}


const char *Field_iterator_table_ref::get_db_name()
{
  if (table_ref->view)
    return table_ref->view_db.str;
  else if (table_ref->is_natural_join)
    return natural_join_it.column_ref()->db_name();

  /*
    Test that TABLE_LIST::db is the same as TABLE_SHARE::db to
    ensure consistency. An exception are I_S schema tables, which
    are inconsistent in this respect.
  */
  DBUG_ASSERT(!strcmp(table_ref->db, table_ref->table->s->db.str) ||
              (table_ref->schema_table &&
               is_infoschema_db(table_ref->table->s->db.str,
                                table_ref->table->s->db.length)));

  return table_ref->db;
}


GRANT_INFO *Field_iterator_table_ref::grant()
{
  if (table_ref->view)
    return &(table_ref->grant);
  else if (table_ref->is_natural_join)
    return natural_join_it.column_ref()->grant();
  return &(table_ref->table->grant);
}


/*
  Create new or return existing column reference to a column of a
  natural/using join.

  SYNOPSIS
    Field_iterator_table_ref::get_or_create_column_ref()
    parent_table_ref  the parent table reference over which the
                      iterator is iterating

  DESCRIPTION
    Create a new natural join column for the current field of the
    iterator if no such column was created, or return an already
    created natural join column. The former happens for base tables or
    views, and the latter for natural/using joins. If a new field is
    created, then the field is added to 'parent_table_ref' if it is
    given, or to the original table referene of the field if
    parent_table_ref == NULL.

  NOTES
    This method is designed so that when a Field_iterator_table_ref
    walks through the fields of a table reference, all its fields
    are created and stored as follows:
    - If the table reference being iterated is a stored table, view or
      natural/using join, store all natural join columns in a list
      attached to that table reference.
    - If the table reference being iterated is a nested join that is
      not natural/using join, then do not materialize its result
      fields. This is OK because for such table references
      Field_iterator_table_ref iterates over the fields of the nested
      table references (recursively). In this way we avoid the storage
      of unnecessay copies of result columns of nested joins.

  RETURN
    #     Pointer to a column of a natural join (or its operand)
    NULL  No memory to allocate the column
*/

Natural_join_column *
Field_iterator_table_ref::get_or_create_column_ref(THD *thd, TABLE_LIST *parent_table_ref)
{
  Natural_join_column *nj_col;
  bool is_created= TRUE;
  uint UNINIT_VAR(field_count);
  TABLE_LIST *add_table_ref= parent_table_ref ?
                             parent_table_ref : table_ref;

  if (field_it == &table_field_it)
  {
    /* The field belongs to a stored table. */
    Field *tmp_field= table_field_it.field();
    Item_field *tmp_item=
      new (thd->mem_root) Item_field(thd, &thd->lex->current_select->context, tmp_field);
    if (!tmp_item)
      return NULL;
    nj_col= new Natural_join_column(tmp_item, table_ref);
    field_count= table_ref->table->s->fields;
  }
  else if (field_it == &view_field_it)
  {
    /* The field belongs to a merge view or information schema table. */
    Field_translator *translated_field= view_field_it.field_translator();
    nj_col= new Natural_join_column(translated_field, table_ref);
    field_count= (uint)(table_ref->field_translation_end -
                 table_ref->field_translation);
  }
  else
  {
    /*
      The field belongs to a NATURAL join, therefore the column reference was
      already created via one of the two constructor calls above. In this case
      we just return the already created column reference.
    */
    DBUG_ASSERT(table_ref->is_join_columns_complete);
    is_created= FALSE;
    nj_col= natural_join_it.column_ref();
    DBUG_ASSERT(nj_col);
  }
  DBUG_ASSERT(!nj_col->table_field || !nj_col->table_field->field ||
              nj_col->table_ref->table == nj_col->table_field->field->table);

  /*
    If the natural join column was just created add it to the list of
    natural join columns of either 'parent_table_ref' or to the table
    reference that directly contains the original field.
  */
  if (is_created)
  {
    /* Make sure not all columns were materialized. */
    DBUG_ASSERT(!add_table_ref->is_join_columns_complete);
    if (!add_table_ref->join_columns)
    {
      /* Create a list of natural join columns on demand. */
      if (!(add_table_ref->join_columns= new List<Natural_join_column>))
        return NULL;
      add_table_ref->is_join_columns_complete= FALSE;
    }
    add_table_ref->join_columns->push_back(nj_col);
    /*
      If new fields are added to their original table reference, mark if
      all fields were added. We do it here as the caller has no easy way
      of knowing when to do it.
      If the fields are being added to parent_table_ref, then the caller
      must take care to mark when all fields are created/added.
    */
    if (!parent_table_ref &&
        add_table_ref->join_columns->elements == field_count)
      add_table_ref->is_join_columns_complete= TRUE;
  }

  return nj_col;
}


/*
  Return an existing reference to a column of a natural/using join.

  SYNOPSIS
    Field_iterator_table_ref::get_natural_column_ref()

  DESCRIPTION
    The method should be called in contexts where it is expected that
    all natural join columns are already created, and that the column
    being retrieved is a Natural_join_column.

  RETURN
    #     Pointer to a column of a natural join (or its operand)
    NULL  We didn't originally have memory to allocate the column
*/

Natural_join_column *
Field_iterator_table_ref::get_natural_column_ref()
{
  Natural_join_column *nj_col;

  DBUG_ASSERT(field_it == &natural_join_it);
  /*
    The field belongs to a NATURAL join, therefore the column reference was
    already created via one of the two constructor calls above. In this case
    we just return the already created column reference.
  */
  nj_col= natural_join_it.column_ref();
  DBUG_ASSERT(nj_col &&
              (!nj_col->table_field || !nj_col->table_field->field ||
               nj_col->table_ref->table == nj_col->table_field->field->table));
  return nj_col;
}

/*****************************************************************************
  Functions to handle column usage bitmaps (read_set, write_set etc...)
*****************************************************************************/

/* Reset all columns bitmaps */

void TABLE::clear_column_bitmaps()
{
  /*
    Reset column read/write usage. It's identical to:
    bitmap_clear_all(&table->def_read_set);
    bitmap_clear_all(&table->def_write_set);
    if (s->virtual_fields) bitmap_clear_all(table->def_vcol_set);
    The code assumes that the bitmaps are allocated after each other, as
    guaranteed by open_table_from_share()
  */
  bzero((char*) def_read_set.bitmap,
        s->column_bitmap_size * (s->virtual_fields ? 3 : 2));
  column_bitmaps_set(&def_read_set, &def_write_set, def_vcol_set);
  rpl_write_set= 0;                             // Safety
}


/*
  Tell handler we are going to call position() and rnd_pos() later.
  
  NOTES:
  This is needed for handlers that uses the primary key to find the
  row. In this case we have to extend the read bitmap with the primary
  key fields.
*/

void TABLE::prepare_for_position()
{
  DBUG_ENTER("TABLE::prepare_for_position");

  if ((file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) &&
      s->primary_key < MAX_KEY)
  {
    mark_columns_used_by_index_no_reset(s->primary_key, read_set);
    /* signal change */
    file->column_bitmaps_signal();
  }
  DBUG_VOID_RETURN;
}


MY_BITMAP *TABLE::prepare_for_keyread(uint index, MY_BITMAP *map)
{
  MY_BITMAP *backup= read_set;
  DBUG_ENTER("TABLE::prepare_for_keyread");
  if (!no_keyread)
    file->ha_start_keyread(index);
  if (map != read_set || !(file->index_flags(index, 0, 1) & HA_CLUSTERED_INDEX))
  {
    mark_columns_used_by_index(index, map);
    column_bitmaps_set(map);
  }
  DBUG_RETURN(backup);
}


/*
  Mark that only fields from one key is used. Useful before keyread.
*/

void TABLE::mark_columns_used_by_index(uint index, MY_BITMAP *bitmap)
{
  DBUG_ENTER("TABLE::mark_columns_used_by_index");

  bitmap_clear_all(bitmap);
  mark_columns_used_by_index_no_reset(index, bitmap);
  DBUG_VOID_RETURN;
}

/*
  Restore to use normal column maps after key read

  NOTES
    This reverse the change done by mark_columns_used_by_index

  WARNING
    For this to work, one must have the normal table maps in place
    when calling mark_columns_used_by_index
*/

void TABLE::restore_column_maps_after_keyread(MY_BITMAP *backup)
{
  DBUG_ENTER("TABLE::restore_column_maps_after_mark_index");
  file->ha_end_keyread();
  read_set= backup;
  file->column_bitmaps_signal();
  DBUG_VOID_RETURN;
}


/*
  mark columns used by key, but don't reset other fields
*/

void TABLE::mark_columns_used_by_index_no_reset(uint index, MY_BITMAP *bitmap)
{
  KEY_PART_INFO *key_part= key_info[index].key_part;
  KEY_PART_INFO *key_part_end= (key_part + key_info[index].user_defined_key_parts);
  for (;key_part != key_part_end; key_part++)
    bitmap_set_bit(bitmap, key_part->fieldnr-1);
  if (file->ha_table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX &&
      s->primary_key != MAX_KEY && s->primary_key != index)
    mark_columns_used_by_index_no_reset(s->primary_key, bitmap);
}


/*
  Mark auto-increment fields as used fields in both read and write maps

  NOTES
    This is needed in insert & update as the auto-increment field is
    always set and sometimes read.
*/

void TABLE::mark_auto_increment_column()
{
  DBUG_ASSERT(found_next_number_field);
  /*
    We must set bit in read set as update_auto_increment() is using the
    store() to check overflow of auto_increment values
  */
  bitmap_set_bit(read_set, found_next_number_field->field_index);
  bitmap_set_bit(write_set, found_next_number_field->field_index);
  if (s->next_number_keypart)
    mark_columns_used_by_index_no_reset(s->next_number_index, read_set);
  file->column_bitmaps_signal();
}


/*
  Mark columns needed for doing an delete of a row

  DESCRIPTON
    Some table engines don't have a cursor on the retrieve rows
    so they need either to use the primary key or all columns to
    be able to delete a row.

    If the engine needs this, the function works as follows:
    - If primary key exits, mark the primary key columns to be read.
    - If not, mark all columns to be read

    If the engine has HA_REQUIRES_KEY_COLUMNS_FOR_DELETE, we will
    mark all key columns as 'to-be-read'. This allows the engine to
    loop over the given record to find all keys and doesn't have to
    retrieve the row again.
*/

void TABLE::mark_columns_needed_for_delete()
{
  bool need_signal= false;
  mark_columns_per_binlog_row_image();

  if (triggers)
    triggers->mark_fields_used(TRG_EVENT_DELETE);
  if (file->ha_table_flags() & HA_REQUIRES_KEY_COLUMNS_FOR_DELETE)
  {
    Field **reg_field;
    for (reg_field= field ; *reg_field ; reg_field++)
    {
      Field *cur_field= *reg_field;
      if (cur_field->flags & (PART_KEY_FLAG | PART_INDIRECT_KEY_FLAG))
      {
        bitmap_set_bit(read_set, cur_field->field_index);
        if (cur_field->vcol_info)
          bitmap_set_bit(vcol_set, cur_field->field_index);
      }
    }
    need_signal= true;
  }
  if (file->ha_table_flags() & HA_PRIMARY_KEY_REQUIRED_FOR_DELETE)
  {
    /*
      If the handler has no cursor capabilites, we have to read either
      the primary key, the hidden primary key or all columns to be
      able to do an delete
    */
    if (s->primary_key == MAX_KEY)
      file->use_hidden_primary_key();
    else
    {
      mark_columns_used_by_index_no_reset(s->primary_key, read_set);
      need_signal= true;
    }
  }
  if (check_constraints)
  {
    mark_check_constraint_columns_for_read();
    need_signal= true;
  }

  if (need_signal)
    file->column_bitmaps_signal();
}


/*
  Mark columns needed for doing an update of a row

  DESCRIPTON
    Some engines needs to have all columns in an update (to be able to
    build a complete row). If this is the case, we mark all not
    updated columns to be read.

    If this is no the case, we do like in the delete case and mark
    if neeed, either the primary key column or all columns to be read.
    (see mark_columns_needed_for_delete() for details)

    If the engine has HA_REQUIRES_KEY_COLUMNS_FOR_DELETE, we will
    mark all USED key columns as 'to-be-read'. This allows the engine to
    loop over the given record to find all changed keys and doesn't have to
    retrieve the row again.
*/

void TABLE::mark_columns_needed_for_update()
{
  DBUG_ENTER("TABLE::mark_columns_needed_for_update");
  bool need_signal= false;

  mark_columns_per_binlog_row_image();

  if (triggers)
    triggers->mark_fields_used(TRG_EVENT_UPDATE);
  if (default_field)
    mark_default_fields_for_write(FALSE);
  if (vfield)
    need_signal|= mark_virtual_columns_for_write(FALSE);
  if (file->ha_table_flags() & HA_REQUIRES_KEY_COLUMNS_FOR_DELETE)
  {
    KEY *end= key_info + s->keys;
    for (KEY *k= key_info; k < end; k++)
    {
      KEY_PART_INFO *kpend= k->key_part + k->ext_key_parts;
      bool any_written= false, all_read= true;
      for (KEY_PART_INFO *kp= k->key_part; kp < kpend; kp++)
      {
        int idx= kp->fieldnr - 1;
        any_written|= bitmap_is_set(write_set, idx);
        all_read&= bitmap_is_set(read_set, idx);
      }
      if (any_written && !all_read)
      {
        for (KEY_PART_INFO *kp= k->key_part; kp < kpend; kp++)
        {
          int idx= kp->fieldnr - 1;
          if (bitmap_fast_test_and_set(read_set, idx))
            continue;
          if (field[idx]->vcol_info)
            mark_virtual_col(field[idx]);
        }
      }
    }
    need_signal= true;
  }
  else
  {
    if (found_next_number_field)
      mark_auto_increment_column();
  }

  if (file->ha_table_flags() & HA_PRIMARY_KEY_REQUIRED_FOR_DELETE)
  {
    /*
      If the handler has no cursor capabilites, we have to read either
      the primary key, the hidden primary key or all columns to be
      able to do an update
    */
    if (s->primary_key == MAX_KEY)
      file->use_hidden_primary_key();
    else
    {
      mark_columns_used_by_index_no_reset(s->primary_key, read_set);
      need_signal= true;
    }
  }
  if (check_constraints)
  {
    mark_check_constraint_columns_for_read();
    need_signal= true;
  }

  /*
    If a timestamp field settable on UPDATE is present then to avoid wrong
    update force the table handler to retrieve write-only fields to be able
    to compare records and detect data change.
  */
  if ((file->ha_table_flags() & HA_PARTIAL_COLUMN_READ) &&
      default_field && s->has_update_default_function)
  {
    bitmap_union(read_set, write_set);
    need_signal= true;
  }
  if (need_signal)
    file->column_bitmaps_signal();
  DBUG_VOID_RETURN;
}


/*
  Mark columns the handler needs for doing an insert

  For now, this is used to mark fields used by the trigger
  as changed.
*/

void TABLE::mark_columns_needed_for_insert()
{
  DBUG_ENTER("mark_columns_needed_for_insert");
  mark_columns_per_binlog_row_image();

  if (triggers)
  {
    /*
      We don't need to mark columns which are used by ON DELETE and
      ON UPDATE triggers, which may be invoked in case of REPLACE or
      INSERT ... ON DUPLICATE KEY UPDATE, since before doing actual
      row replacement or update write_record() will mark all table
      fields as used.
    */
    triggers->mark_fields_used(TRG_EVENT_INSERT);
  }
  if (found_next_number_field)
    mark_auto_increment_column();
  if (default_field)
    mark_default_fields_for_write(TRUE);
  /* Mark virtual columns for insert */
  if (vfield)
    mark_virtual_columns_for_write(TRUE);
  if (check_constraints)
    mark_check_constraint_columns_for_read();
  DBUG_VOID_RETURN;
}

/*
  Mark columns according the binlog row image option.

  Columns to be written are stored in 'rpl_write_set'

  When logging in RBR, the user can select whether to
  log partial or full rows, depending on the table
  definition, and the value of binlog_row_image.

  Semantics of the binlog_row_image are the following
  (PKE - primary key equivalent, ie, PK fields if PK
  exists, all fields otherwise):

  binlog_row_image= MINIMAL
    - This marks the PKE fields in the read_set
    - This marks all fields where a value was specified
      in the rpl_write_set

  binlog_row_image= NOBLOB
    - This marks PKE + all non-blob fields in the read_set
    - This marks all fields where a value was specified
      and all non-blob fields in the rpl_write_set

  binlog_row_image= FULL
    - all columns in the read_set
    - all columns in the rpl_write_set

  This marking is done without resetting the original
  bitmaps. This means that we will strip extra fields in
  the read_set at binlogging time (for those cases that
  we only want to log a PK and we needed other fields for
  execution).
*/

void TABLE::mark_columns_per_binlog_row_image()
{
  THD *thd= in_use;
  DBUG_ENTER("mark_columns_per_binlog_row_image");
  DBUG_ASSERT(read_set->bitmap);
  DBUG_ASSERT(write_set->bitmap);

  /* If not using row format */
  rpl_write_set= write_set;

  /**
    If in RBR we may need to mark some extra columns,
    depending on the binlog-row-image command line argument.
   */
  if ((WSREP_EMULATE_BINLOG(thd) || mysql_bin_log.is_open()) &&
      thd->is_current_stmt_binlog_format_row() &&
      !ha_check_storage_engine_flag(s->db_type(), HTON_NO_BINLOG_ROW_OPT))
  {
    /* if there is no PK, then mark all columns for the BI. */
    if (s->primary_key >= MAX_KEY)
    {
      bitmap_set_all(read_set);
      rpl_write_set= read_set;
    }
    else
    {
      switch (thd->variables.binlog_row_image) {
      case BINLOG_ROW_IMAGE_FULL:
        bitmap_set_all(read_set);
        /* Set of columns that should be written (all) */
        rpl_write_set= read_set;
        break;
      case BINLOG_ROW_IMAGE_NOBLOB:
        /* Only write changed columns + not blobs */
        rpl_write_set= &def_rpl_write_set;
        bitmap_copy(rpl_write_set, write_set);

        /*
          for every field that is not set, mark it unless it is a blob or
          part of a primary key
        */
        for (Field **ptr=field ; *ptr ; ptr++)
        {
          Field *my_field= *ptr;
          /*
            bypass blob fields. These can be set or not set, we don't care.
            Later, at binlogging time, if we don't need them in the before
            image, we will discard them.

            If set in the AI, then the blob is really needed, there is
            nothing we can do about it.
          */
          if ((my_field->flags & PRI_KEY_FLAG) ||
              (my_field->type() != MYSQL_TYPE_BLOB))
          {
            bitmap_set_bit(read_set, my_field->field_index);
            bitmap_set_bit(rpl_write_set, my_field->field_index);
          }
        }
        break;
      case BINLOG_ROW_IMAGE_MINIMAL:
        /*
          mark the primary key in the read set so that we can find the row
          that is updated / deleted.
          We don't need to mark the primary key in the rpl_write_set as the
          binary log will include all columns read anyway.
        */
        mark_columns_used_by_index_no_reset(s->primary_key, read_set);
        /* Only write columns that have changed */
        rpl_write_set= write_set;
        break;

      default:
        DBUG_ASSERT(FALSE);
      }
    }
    /*
      We have to ensure that all virtual columns that are part of read set
      are calculated.
    */
    if (vcol_set)
      bitmap_union(vcol_set, read_set);
    file->column_bitmaps_signal();
  }

  DBUG_VOID_RETURN;
}

/*
   @brief Mark a column as virtual used by the query

   @param field           the field for the column to be marked

   @details
     The function marks the column for 'field' as virtual (computed)
     in the bitmap vcol_set.
     If the column is marked for the first time the expression to compute
     the column is traversed and all columns that are occurred there are
     marked in the read_set of the table.

   @retval
     TRUE       if column is marked for the first time
   @retval
     FALSE      otherwise
*/

bool TABLE::mark_virtual_col(Field *field)
{
  bool res;
  DBUG_ASSERT(field->vcol_info);
  if (!(res= bitmap_fast_test_and_set(vcol_set, field->field_index)))
  {
    Item *vcol_item= field->vcol_info->expr;
    DBUG_ASSERT(vcol_item);
    vcol_item->walk(&Item::register_field_in_read_map, 1, 0);
  }
  return res;
}


/* 
  @brief Mark virtual columns for update/insert commands

  @param insert_fl    true if virtual columns are marked for insert command
                      For the moment this is not used, may be used in future.

  @details
    The function marks virtual columns used in a update/insert commands
    in the vcol_set bitmap.
    For an insert command a virtual column is always marked in write_set if
    it is a stored column.
    If a virtual column is from write_set it is always marked in vcol_set.
    If a stored virtual column is not from write_set but it is computed
    through columns from write_set it is also marked in vcol_set, and,
    besides, it is added to write_set. 

  @return whether a bitmap was updated

  @note
    Let table t1 have columns a,b,c and let column c be a stored virtual 
    column computed through columns a and b. Then for the query
      UPDATE t1 SET a=1
    column c will be placed into vcol_set and into write_set while
    column b will be placed into read_set.
    If column c was a virtual column, but not a stored virtual column
    then it would not be added to any of the sets. Column b would not
    be added to read_set either.
*/

bool TABLE::mark_virtual_columns_for_write(bool insert_fl
                                           __attribute__((unused)))
{
  Field **vfield_ptr, *tmp_vfield;
  bool bitmap_updated= false;
  DBUG_ENTER("mark_virtual_columns_for_write");

  for (vfield_ptr= vfield; *vfield_ptr; vfield_ptr++)
  {
    tmp_vfield= *vfield_ptr;
    if (bitmap_is_set(write_set, tmp_vfield->field_index))
      bitmap_updated|= mark_virtual_col(tmp_vfield);
    else if (tmp_vfield->vcol_info->stored_in_db ||
             (tmp_vfield->flags & (PART_KEY_FLAG | FIELD_IN_PART_FUNC_FLAG |
                                   PART_INDIRECT_KEY_FLAG)))
    {
      bitmap_set_bit(write_set, tmp_vfield->field_index);
      mark_virtual_col(tmp_vfield);
      bitmap_updated= true;
    }
  }
  if (bitmap_updated)
    file->column_bitmaps_signal();
  DBUG_RETURN(bitmap_updated);
}

/*
  Mark fields used by check constraints into s->check_set.
  Mark all fields used in an expression that is part of an index
  with PART_INDIRECT_KEY_FLAG

  This is done once for the TABLE_SHARE the first time the table is opened.
  The marking must be done non-destructively to handle the case when
  this could be run in parallely by two threads
*/

void TABLE::mark_columns_used_by_virtual_fields(void)
{
  MY_BITMAP *save_read_set;
  Field **vfield_ptr;
  TABLE_SHARE::enum_v_keys v_keys= TABLE_SHARE::NO_V_KEYS;

  /* If there is virtual fields are already initialized */
  if (s->check_set_initialized)
    return;

  if (s->tmp_table == NO_TMP_TABLE)
    mysql_mutex_lock(&s->LOCK_share);
  if (s->check_set)
  {
    /* Mark fields used by check constraint */
    save_read_set= read_set;
    read_set= s->check_set;

    for (Virtual_column_info **chk= check_constraints ; *chk ; chk++)
      (*chk)->expr->walk(&Item::register_field_in_read_map, 1, 0);
    read_set= save_read_set;
  }

  /*
    mark all fields that part of a virtual indexed field with
    PART_INDIRECT_KEY_FLAG. This is used to ensure that all fields
    that are part of an index exits before write/delete/update.

    As this code is only executed once per open share, it's reusing
    existing functionality instead of adding an extra argument to
    add_field_to_set_processor or adding another processor.
  */
  if (vfield)
  {
    for (vfield_ptr= vfield; *vfield_ptr; vfield_ptr++)
    {
      if ((*vfield_ptr)->flags & PART_KEY_FLAG)
        (*vfield_ptr)->vcol_info->expr->walk(&Item::add_field_to_set_processor,
                                             1, this);
    }
    for (uint i= 0 ; i < s->fields ; i++)
    {
      if (bitmap_is_set(&tmp_set, i))
      {
        s->field[i]->flags|= PART_INDIRECT_KEY_FLAG;
        v_keys= TABLE_SHARE::V_KEYS;
      }
    }
    bitmap_clear_all(&tmp_set);
  }
  s->check_set_initialized= v_keys;
  if (s->tmp_table == NO_TMP_TABLE)
    mysql_mutex_unlock(&s->LOCK_share);
}

/* Add fields used by CHECK CONSTRAINT to read map */

void TABLE::mark_check_constraint_columns_for_read(void)
{
  bitmap_union(read_set, s->check_set);
  if (vcol_set)
    bitmap_union(vcol_set, s->check_set);
}


/**
  Add all fields that have a default function to the table write set.
*/

void TABLE::mark_default_fields_for_write(bool is_insert)
{
  DBUG_ENTER("mark_default_fields_for_write");
  Field **field_ptr, *field;
  for (field_ptr= default_field; *field_ptr; field_ptr++)
  {
    field= (*field_ptr);
    if (is_insert && field->default_value)
    {
      bitmap_set_bit(write_set, field->field_index);
      field->default_value->expr->
        walk(&Item::register_field_in_read_map, 1, 0);
    }
    else if (!is_insert && field->has_update_default_function())
      bitmap_set_bit(write_set, field->field_index);
  }
  DBUG_VOID_RETURN;
}

void TABLE::move_fields(Field **ptr, const uchar *to, const uchar *from)
{
  my_ptrdiff_t diff= to - from;
  if (diff)
  {
    do
    {
      (*ptr)->move_field_offset(diff);
    } while (*(++ptr));
  }
}


/*
  Store all allocated virtual fields blob values
  Used by InnoDB when calculating virtual fields for it's own internal
  records
*/

void TABLE::remember_blob_values(String *blob_storage)
{
  Field **vfield_ptr;
  for (vfield_ptr= vfield; *vfield_ptr; vfield_ptr++)
  {
    if ((*vfield_ptr)->type() == MYSQL_TYPE_BLOB &&
        !(*vfield_ptr)->vcol_info->stored_in_db)
    {
      Field_blob *blob= ((Field_blob*) *vfield_ptr);
      memcpy((void*) blob_storage, (void*) &blob->value, sizeof(blob->value));
      blob_storage++;
      blob->value.release();
    }
  }
}


/*
  Restore all allocated virtual fields blob values
  Used by InnoDB when calculating virtual fields for it's own internal
  records
*/

void TABLE::restore_blob_values(String *blob_storage)
{
  Field **vfield_ptr;
  for (vfield_ptr= vfield; *vfield_ptr; vfield_ptr++)
  {
    if ((*vfield_ptr)->type() == MYSQL_TYPE_BLOB &&
        !(*vfield_ptr)->vcol_info->stored_in_db)
    {
      Field_blob *blob= ((Field_blob*) *vfield_ptr);
      blob->value.free();
      memcpy((void*) &blob->value, (void*) blob_storage, sizeof(blob->value));
      blob_storage++;
    }
  }
}


/**
  @brief
  Allocate space for keys

  @param key_count  number of keys to allocate additionally

  @details
  The function allocates memory  to fit additionally 'key_count' keys 
  for this table.

  @return FALSE   space was successfully allocated
  @return TRUE    an error occur
*/

bool TABLE::alloc_keys(uint key_count)
{
  key_info= (KEY*) alloc_root(&mem_root, sizeof(KEY)*(s->keys+key_count));
  if (s->keys)
    memmove(key_info, s->key_info, sizeof(KEY)*s->keys);
  s->key_info= key_info;
  max_keys= s->keys+key_count;
  return !(key_info);
}


/**
  @brief
  Populate a KEY_PART_INFO structure with the data related to a field entry.

  @param key_part_info  The structure to fill.
  @param field          The field entry that represents the key part.
  @param fleldnr        The number of the field, count starting from 1.

  TODO: This method does not make use of any table specific fields. It
  could be refactored to act as a constructor for KEY_PART_INFO instead.
*/

void TABLE::create_key_part_by_field(KEY_PART_INFO *key_part_info,
                                     Field *field, uint fieldnr)
{
  DBUG_ASSERT(field->field_index + 1 == (int)fieldnr);
  key_part_info->null_bit= field->null_bit;
  key_part_info->null_offset= (uint) (field->null_ptr -
                                      (uchar*) record[0]);
  key_part_info->field= field;
  key_part_info->fieldnr= fieldnr;
  key_part_info->offset= field->offset(record[0]);
  /*
     field->key_length() accounts for the raw length of the field, excluding
     any metadata such as length of field or the NULL flag.
  */
  key_part_info->length= (uint16) field->key_length();
  key_part_info->key_part_flag= 0;
  /* TODO:
    The below method of computing the key format length of the
    key part is a copy/paste from opt_range.cc, and table.cc.
    This should be factored out, e.g. as a method of Field.
    In addition it is not clear if any of the Field::*_length
    methods is supposed to compute the same length. If so, it
    might be reused.
  */
  key_part_info->store_length= key_part_info->length;
  /*
    For BIT fields null_bit is not set to 0 even if the field is defined
    as NOT NULL, look at Field_bit::Field_bit
  */
  if (!field->real_maybe_null())
  {
    key_part_info->null_bit= 0;
  }

  /*
     The total store length of the key part is the raw length of the field +
     any metadata information, such as its length for strings and/or the null
     flag.
  */
  if (field->real_maybe_null())
  {
    key_part_info->store_length+= HA_KEY_NULL_LENGTH;
  }
  if (field->type() == MYSQL_TYPE_BLOB || 
      field->type() == MYSQL_TYPE_GEOMETRY ||
      field->real_type() == MYSQL_TYPE_VARCHAR)
  {
    key_part_info->store_length+= HA_KEY_BLOB_LENGTH;
    key_part_info->key_part_flag|=
      field->type() == MYSQL_TYPE_BLOB ? HA_BLOB_PART: HA_VAR_LENGTH_PART;
  }

  key_part_info->type=     (uint8) field->key_type();
  key_part_info->key_type =
    ((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
    (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT1 ||
    (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT2) ?
    0 : FIELDFLAG_BINARY;
}


/**
  @brief
  Check validity of a possible key for the derived table

  @param key            the number of the key
  @param key_parts      number of components of the key
  @param next_field_no  the call-back function that returns the number of
                        the field used as the next component of the key
  @param arg            the argument for the above function

  @details
  The function checks whether a possible key satisfies the constraints
  imposed on the keys of any temporary table.

  We need to filter out BLOB columns here, because ref access optimizer creates
  KEYUSE objects for equalities for non-key columns for two puproses:
  1. To discover possible keys for derived_with_keys optimization
  2. To do hash joins
  For the purpose of #1, KEYUSE objects are not created for "blob_column=..." .
  However, they might be created for #2. In order to catch that case, we filter
  them out here.

  @return TRUE if the key is valid
  @return FALSE otherwise
*/

bool TABLE::check_tmp_key(uint key, uint key_parts,
                          uint (*next_field_no) (uchar *), uchar *arg)
{
  Field **reg_field;
  uint i;
  uint key_len= 0;

  for (i= 0; i < key_parts; i++)
  {
    uint fld_idx= next_field_no(arg);
    reg_field= field + fld_idx;
    if ((*reg_field)->type() == MYSQL_TYPE_BLOB)
      return FALSE;
    uint fld_store_len= (uint16) (*reg_field)->key_length();
    if ((*reg_field)->real_maybe_null())
      fld_store_len+= HA_KEY_NULL_LENGTH;
    if ((*reg_field)->real_type() == MYSQL_TYPE_VARCHAR ||
        (*reg_field)->type() == MYSQL_TYPE_GEOMETRY)
      fld_store_len+= HA_KEY_BLOB_LENGTH;
    key_len+= fld_store_len;
  }
  /*
    We use MI_MAX_KEY_LENGTH (myisam's default) below because it is
    smaller than MAX_KEY_LENGTH (heap's default) and it's unknown whether
    myisam or heap will be used for the temporary table.
  */
  return key_len <= MI_MAX_KEY_LENGTH;
}

/**
  @brief
  Add one key to a temporary table

  @param key            the number of the key
  @param key_parts      number of components of the key
  @param next_field_no  the call-back function that returns the number of
                        the field used as the next component of the key
  @param arg            the argument for the above function
  @param unique         TRUE <=> it is a unique index

  @details
  The function adds a new key to the table that is assumed to be a temporary
  table. At each its invocation the call-back function must return
  the number of the field that is used as the next component of this key.

  @return FALSE is a success
  @return TRUE if a failure

*/

bool TABLE::add_tmp_key(uint key, uint key_parts,
                        uint (*next_field_no) (uchar *), uchar *arg,
                        bool unique)
{
  DBUG_ASSERT(key < max_keys);

  char buf[NAME_CHAR_LEN];
  KEY* keyinfo;
  Field **reg_field;
  uint i;

  bool key_start= TRUE;
  KEY_PART_INFO* key_part_info=
      (KEY_PART_INFO*) alloc_root(&mem_root, sizeof(KEY_PART_INFO)*key_parts);
  if (!key_part_info)
    return TRUE;
  keyinfo= key_info + key;
  keyinfo->key_part= key_part_info;
  keyinfo->usable_key_parts= keyinfo->user_defined_key_parts = key_parts;
  keyinfo->ext_key_parts= keyinfo->user_defined_key_parts;
  keyinfo->key_length=0;
  keyinfo->algorithm= HA_KEY_ALG_UNDEF;
  keyinfo->flags= HA_GENERATED_KEY;
  keyinfo->ext_key_flags= keyinfo->flags;
  keyinfo->is_statistics_from_stat_tables= FALSE;
  if (unique)
    keyinfo->flags|= HA_NOSAME;
  sprintf(buf, "key%i", key);
  if (!(keyinfo->name= strdup_root(&mem_root, buf)))
    return TRUE;
  keyinfo->rec_per_key= (ulong*) alloc_root(&mem_root,
                                            sizeof(ulong)*key_parts);
  if (!keyinfo->rec_per_key)
    return TRUE;
  bzero(keyinfo->rec_per_key, sizeof(ulong)*key_parts);
  keyinfo->read_stats= NULL;
  keyinfo->collected_stats= NULL;

  for (i= 0; i < key_parts; i++)
  {
    uint fld_idx= next_field_no(arg); 
    reg_field= field + fld_idx;
    if (key_start)
      (*reg_field)->key_start.set_bit(key);
    (*reg_field)->part_of_key.set_bit(key);
    create_key_part_by_field(key_part_info, *reg_field, fld_idx+1);
    keyinfo->key_length += key_part_info->store_length;
    (*reg_field)->flags|= PART_KEY_FLAG;
    key_start= FALSE;
    key_part_info++;
  }

  set_if_bigger(s->max_key_length, keyinfo->key_length);
  s->keys++;
  return FALSE;
}

/*
  @brief
  Drop all indexes except specified one.

  @param key_to_save the key to save

  @details
  Drop all indexes on this table except 'key_to_save'. The saved key becomes
  key #0. Memory occupied by key parts of dropped keys are freed.
  If the 'key_to_save' is negative then all keys are freed.
*/

void TABLE::use_index(int key_to_save)
{
  uint i= 1;
  DBUG_ASSERT(!created && key_to_save < (int)s->keys);
  if (key_to_save >= 0)
    /* Save the given key. */
    memmove(key_info, key_info + key_to_save, sizeof(KEY));
  else
    /* Drop all keys; */
    i= 0;

  s->keys= i;
}

/*
  Return TRUE if the table is filled at execution phase 
  
  (and so, the optimizer must not do anything that depends on the contents of
   the table, like range analysis or constant table detection)
*/

bool TABLE::is_filled_at_execution()
{ 
  /*
    pos_in_table_list == NULL for internal temporary tables because they
    do not have a corresponding table reference. Such tables are filled
    during execution.
  */
  return MY_TEST(!pos_in_table_list ||
                 pos_in_table_list->jtbm_subselect ||
                 pos_in_table_list->is_active_sjm());
}


/**
  @brief
  Get actual number of key components

  @param keyinfo

  @details
  The function calculates actual number of key components, possibly including
  components of extended keys, taken into consideration by the optimizer for the
  key described by the parameter keyinfo.

  @return number of considered key components
*/ 

uint TABLE::actual_n_key_parts(KEY *keyinfo)
{
  return optimizer_flag(in_use, OPTIMIZER_SWITCH_EXTENDED_KEYS) ?
           keyinfo->ext_key_parts : keyinfo->user_defined_key_parts;
}

 
/**
  @brief
  Get actual key flags for a table key 

  @param keyinfo

  @details
  The function finds out actual key flags taken into consideration by the
  optimizer for the key described by the parameter keyinfo.

  @return actual key flags
*/ 

ulong TABLE::actual_key_flags(KEY *keyinfo)
{
  return optimizer_flag(in_use, OPTIMIZER_SWITCH_EXTENDED_KEYS) ?
           keyinfo->ext_key_flags : keyinfo->flags;
} 


/*
  Cleanup this table for re-execution.

  SYNOPSIS
    TABLE_LIST::reinit_before_use()
*/

void TABLE_LIST::reinit_before_use(THD *thd)
{
  /*
    Reset old pointers to TABLEs: they are not valid since the tables
    were closed in the end of previous prepare or execute call.
  */
  table= 0;
  /* Reset is_schema_table_processed value(needed for I_S tables */
  schema_table_state= NOT_PROCESSED;

  TABLE_LIST *embedded; /* The table at the current level of nesting. */
  TABLE_LIST *parent_embedding= this; /* The parent nested table reference. */
  do
  {
    embedded= parent_embedding;
    if (embedded->prep_on_expr)
      embedded->on_expr= embedded->prep_on_expr->copy_andor_structure(thd);
    parent_embedding= embedded->embedding;
  }
  while (parent_embedding &&
         parent_embedding->nested_join->join_list.head() == embedded);

  mdl_request.ticket= NULL;
}


/*
  Return subselect that contains the FROM list this table is taken from

  SYNOPSIS
    TABLE_LIST::containing_subselect()
 
  RETURN
    Subselect item for the subquery that contains the FROM list
    this table is taken from if there is any
    0 - otherwise

*/

Item_subselect *TABLE_LIST::containing_subselect()
{
  return (select_lex ? select_lex->master_unit()->item : 0);
}

/*
  Compiles the tagged hints list and fills up the bitmasks.

  SYNOPSIS
    process_index_hints()
      table         the TABLE to operate on.

  DESCRIPTION
    The parser collects the index hints for each table in a "tagged list" 
    (TABLE_LIST::index_hints). Using the information in this tagged list
    this function sets the members TABLE::keys_in_use_for_query,
    TABLE::keys_in_use_for_group_by, TABLE::keys_in_use_for_order_by,
    TABLE::force_index, TABLE::force_index_order,
    TABLE::force_index_group and TABLE::covering_keys.

    Current implementation of the runtime does not allow mixing FORCE INDEX
    and USE INDEX, so this is checked here. Then the FORCE INDEX list 
    (if non-empty) is appended to the USE INDEX list and a flag is set.

    Multiple hints of the same kind are processed so that each clause 
    is applied to what is computed in the previous clause.
    For example:
        USE INDEX (i1) USE INDEX (i2)
    is equivalent to
        USE INDEX (i1,i2)
    and means "consider only i1 and i2".

    Similarly
        USE INDEX () USE INDEX (i1)
    is equivalent to
        USE INDEX (i1)
    and means "consider only the index i1"

    It is OK to have the same index several times, e.g. "USE INDEX (i1,i1)" is
    not an error.

    Different kind of hints (USE/FORCE/IGNORE) are processed in the following
    order:
      1. All indexes in USE (or FORCE) INDEX are added to the mask.
      2. All IGNORE INDEX

    e.g. "USE INDEX i1, IGNORE INDEX i1, USE INDEX i1" will not use i1 at all
    as if we had "USE INDEX i1, USE INDEX i1, IGNORE INDEX i1".

    As an optimization if there is a covering index, and we have 
    IGNORE INDEX FOR GROUP/ORDER, and this index is used for the JOIN part, 
    then we have to ignore the IGNORE INDEX FROM GROUP/ORDER.

  RETURN VALUE
    FALSE                no errors found
    TRUE                 found and reported an error.
*/
bool TABLE_LIST::process_index_hints(TABLE *tbl)
{
  /* initialize the result variables */
  tbl->keys_in_use_for_query= tbl->keys_in_use_for_group_by= 
    tbl->keys_in_use_for_order_by= tbl->s->keys_in_use;

  /* index hint list processing */
  if (index_hints)
  {
    key_map index_join[INDEX_HINT_FORCE + 1];
    key_map index_order[INDEX_HINT_FORCE + 1];
    key_map index_group[INDEX_HINT_FORCE + 1];
    Index_hint *hint;
    int type;
    bool have_empty_use_join= FALSE, have_empty_use_order= FALSE, 
         have_empty_use_group= FALSE;
    List_iterator <Index_hint> iter(*index_hints);

    /* initialize temporary variables used to collect hints of each kind */
    for (type= INDEX_HINT_IGNORE; type <= INDEX_HINT_FORCE; type++)
    {
      index_join[type].clear_all();
      index_order[type].clear_all();
      index_group[type].clear_all();
    }

    /* iterate over the hints list */
    while ((hint= iter++))
    {
      uint pos;

      /* process empty USE INDEX () */
      if (hint->type == INDEX_HINT_USE && !hint->key_name.str)
      {
        if (hint->clause & INDEX_HINT_MASK_JOIN)
        {
          index_join[hint->type].clear_all();
          have_empty_use_join= TRUE;
        }
        if (hint->clause & INDEX_HINT_MASK_ORDER)
        {
          index_order[hint->type].clear_all();
          have_empty_use_order= TRUE;
        }
        if (hint->clause & INDEX_HINT_MASK_GROUP)
        {
          index_group[hint->type].clear_all();
          have_empty_use_group= TRUE;
        }
        continue;
      }

      /* 
        Check if an index with the given name exists and get his offset in 
        the keys bitmask for the table 
      */
      if (tbl->s->keynames.type_names == 0 ||
          (pos= find_type(&tbl->s->keynames, hint->key_name.str,
                          hint->key_name.length, 1)) <= 0)
      {
        my_error(ER_KEY_DOES_NOT_EXITS, MYF(0), hint->key_name.str, alias);
        return 1;
      }

      pos--;

      /* add to the appropriate clause mask */
      if (hint->clause & INDEX_HINT_MASK_JOIN)
        index_join[hint->type].set_bit (pos);
      if (hint->clause & INDEX_HINT_MASK_ORDER)
        index_order[hint->type].set_bit (pos);
      if (hint->clause & INDEX_HINT_MASK_GROUP)
        index_group[hint->type].set_bit (pos);
    }

    /* cannot mix USE INDEX and FORCE INDEX */
    if ((!index_join[INDEX_HINT_FORCE].is_clear_all() ||
         !index_order[INDEX_HINT_FORCE].is_clear_all() ||
         !index_group[INDEX_HINT_FORCE].is_clear_all()) &&
        (!index_join[INDEX_HINT_USE].is_clear_all() ||  have_empty_use_join ||
         !index_order[INDEX_HINT_USE].is_clear_all() || have_empty_use_order ||
         !index_group[INDEX_HINT_USE].is_clear_all() || have_empty_use_group))
    {
      my_error(ER_WRONG_USAGE, MYF(0), index_hint_type_name[INDEX_HINT_USE],
               index_hint_type_name[INDEX_HINT_FORCE]);
      return 1;
    }

    /* process FORCE INDEX as USE INDEX with a flag */
    if (!index_order[INDEX_HINT_FORCE].is_clear_all())
    {
      tbl->force_index_order= TRUE;
      index_order[INDEX_HINT_USE].merge(index_order[INDEX_HINT_FORCE]);
    }

    if (!index_group[INDEX_HINT_FORCE].is_clear_all())
    {
      tbl->force_index_group= TRUE;
      index_group[INDEX_HINT_USE].merge(index_group[INDEX_HINT_FORCE]);
    }

    /*
      TODO: get rid of tbl->force_index (on if any FORCE INDEX is specified)
      and create tbl->force_index_join instead.
      Then use the correct force_index_XX instead of the global one.
    */
    if (!index_join[INDEX_HINT_FORCE].is_clear_all() ||
        tbl->force_index_group || tbl->force_index_order)
    {
      tbl->force_index= TRUE;
      index_join[INDEX_HINT_USE].merge(index_join[INDEX_HINT_FORCE]);
    }

    /* apply USE INDEX */
    if (!index_join[INDEX_HINT_USE].is_clear_all() || have_empty_use_join)
      tbl->keys_in_use_for_query.intersect(index_join[INDEX_HINT_USE]);
    if (!index_order[INDEX_HINT_USE].is_clear_all() || have_empty_use_order)
      tbl->keys_in_use_for_order_by.intersect (index_order[INDEX_HINT_USE]);
    if (!index_group[INDEX_HINT_USE].is_clear_all() || have_empty_use_group)
      tbl->keys_in_use_for_group_by.intersect (index_group[INDEX_HINT_USE]);

    /* apply IGNORE INDEX */
    tbl->keys_in_use_for_query.subtract (index_join[INDEX_HINT_IGNORE]);
    tbl->keys_in_use_for_order_by.subtract (index_order[INDEX_HINT_IGNORE]);
    tbl->keys_in_use_for_group_by.subtract (index_group[INDEX_HINT_IGNORE]);
  }

  /* make sure covering_keys don't include indexes disabled with a hint */
  tbl->covering_keys.intersect(tbl->keys_in_use_for_query);
  return 0;
}


size_t max_row_length(TABLE *table, MY_BITMAP const *cols, const uchar *data)
{
  TABLE_SHARE *table_s= table->s;
  size_t length= table_s->reclength + 2 * table_s->fields;
  uint *const beg= table_s->blob_field;
  uint *const end= beg + table_s->blob_fields;
  my_ptrdiff_t const rec_offset= (my_ptrdiff_t) (data - table->record[0]);
  DBUG_ENTER("max_row_length");

  for (uint *ptr= beg ; ptr != end ; ++ptr)
  {
    Field * const field= table->field[*ptr];
    if (bitmap_is_set(cols, field->field_index) &&
        !field->is_null(rec_offset))
    {
      Field_blob * const blob= (Field_blob*) field;
      length+= blob->get_length(rec_offset) + 8; /* max blob store length */
    }
  }
  DBUG_PRINT("exit", ("length: %lld", (longlong) length));
  DBUG_RETURN(length);
}


/**
   Helper function which allows to allocate metadata lock request
   objects for all elements of table list.
*/

void init_mdl_requests(TABLE_LIST *table_list)
{
  for ( ; table_list ; table_list= table_list->next_global)
    table_list->mdl_request.init(MDL_key::TABLE,
                                 table_list->db, table_list->table_name,
                                 table_list->lock_type >= TL_WRITE_ALLOW_WRITE ?
                                 MDL_SHARED_WRITE : MDL_SHARED_READ,
                                 MDL_TRANSACTION);
}


/**
  Update TABLE::const_key_parts for single table UPDATE/DELETE query

  @param conds               WHERE clause expression

  @retval TRUE   error (OOM)
  @retval FALSE  success

  @note
    Set const_key_parts bits if key fields are equal to constants in
    the WHERE expression.
*/

bool TABLE::update_const_key_parts(COND *conds)
{
  bzero((char*) const_key_parts, sizeof(key_part_map) * s->keys);

  if (conds == NULL)
    return FALSE;

  for (uint index= 0; index < s->keys; index++)
  {
    KEY_PART_INFO *keyinfo= key_info[index].key_part;
    KEY_PART_INFO *keyinfo_end= keyinfo + key_info[index].user_defined_key_parts;

    for (key_part_map part_map= (key_part_map)1; 
        keyinfo < keyinfo_end;
        keyinfo++, part_map<<= 1)
    {
      if (const_expression_in_where(conds, NULL, keyinfo->field))
        const_key_parts[index]|= part_map;
    }
  }
  return FALSE;
}

/**
  Test if the order list consists of simple field expressions

  @param order                Linked list of ORDER BY arguments

  @return TRUE if @a order is empty or consist of simple field expressions
*/

bool is_simple_order(ORDER *order)
{
  for (ORDER *ord= order; ord; ord= ord->next)
  {
    if (ord->item[0]->real_item()->type() != Item::FIELD_ITEM)
      return FALSE;
  }
  return TRUE;
}

class Turn_errors_to_warnings_handler : public Internal_error_handler
{
public:
  Turn_errors_to_warnings_handler() {}
  bool handle_condition(THD *thd,
                        uint sql_errno,
                        const char* sqlstate,
                        Sql_condition::enum_warning_level *level,
                        const char* msg,
                        Sql_condition ** cond_hdl)
  {
    *cond_hdl= NULL;
    if (*level == Sql_condition::WARN_LEVEL_ERROR)
      *level= Sql_condition::WARN_LEVEL_WARN;
    return(0);
  }
};

/*
  @brief Compute values for virtual columns used in query

  @param  update_mode Specifies what virtual column are computed
  
  @details
    The function computes the values of the virtual columns of the table and
    stores them in the table record buffer.

  @retval
    0    Success
  @retval
    >0   Error occurred when storing a virtual field value
*/

int TABLE::update_virtual_fields(handler *h, enum_vcol_update_mode update_mode)
{
  DBUG_ENTER("TABLE::update_virtual_fields");
  DBUG_PRINT("enter", ("update_mode: %d", update_mode));
  Field **vfield_ptr, *vf;
  Query_arena backup_arena;
  Turn_errors_to_warnings_handler Suppress_errors;
  int error;
  bool handler_pushed= 0, update_all_columns= 1;
  DBUG_ASSERT(vfield);

  if (h->keyread_enabled())
    DBUG_RETURN(0);

  error= 0;
  in_use->set_n_backup_active_arena(expr_arena, &backup_arena);

  /* When reading or deleting row, ignore errors from virtual columns */
  if (update_mode == VCOL_UPDATE_FOR_READ ||
      update_mode == VCOL_UPDATE_FOR_DELETE ||
      update_mode == VCOL_UPDATE_INDEXED)
  {
    in_use->push_internal_handler(&Suppress_errors);
    handler_pushed= 1;
  }
  else if (update_mode == VCOL_UPDATE_FOR_REPLACE &&
           in_use->is_current_stmt_binlog_format_row() &&
           in_use->variables.binlog_row_image != BINLOG_ROW_IMAGE_MINIMAL)
  {
    /*
      If we are doing a replace with not minimal binary logging, we have to
      calculate all virtual columns.
    */
    update_all_columns= 1;
  }

  /* Iterate over virtual fields in the table */
  for (vfield_ptr= vfield; *vfield_ptr; vfield_ptr++)
  {
    vf= (*vfield_ptr);
    Virtual_column_info *vcol_info= vf->vcol_info;
    DBUG_ASSERT(vcol_info);
    DBUG_ASSERT(vcol_info->expr);

    bool update= 0, swap_values= 0;
    switch (update_mode) {
    case VCOL_UPDATE_FOR_READ:
      update= (!vcol_info->stored_in_db &&
               bitmap_is_set(vcol_set, vf->field_index));
      swap_values= 1;
      break;
    case VCOL_UPDATE_FOR_DELETE:
    case VCOL_UPDATE_FOR_WRITE:
      update= bitmap_is_set(vcol_set, vf->field_index);
      break;
    case VCOL_UPDATE_FOR_REPLACE:
      update= ((!vcol_info->stored_in_db &&
                (vf->flags & (PART_KEY_FLAG | PART_INDIRECT_KEY_FLAG)) &&
                bitmap_is_set(vcol_set, vf->field_index)) ||
               update_all_columns);
      if (update && (vf->flags & BLOB_FLAG))
      {
        /*
          The row has been read into record[1] and Field_blob::value
          contains the value for record[0].  Swap value and read_value
          to ensure that the virtual column data for the read row will
          be in read_value at the end of this function
        */
        ((Field_blob*) vf)->swap_value_and_read_value();
        /* Ensure we call swap_value_and_read_value() after update */
        swap_values= 1;
      }
      break;
    case VCOL_UPDATE_INDEXED:
    case VCOL_UPDATE_INDEXED_FOR_UPDATE:
      /* Read indexed fields that was not updated in VCOL_UPDATE_FOR_READ */
      update= (!vcol_info->stored_in_db &&
               (vf->flags & (PART_KEY_FLAG | PART_INDIRECT_KEY_FLAG)) &&
               !bitmap_is_set(vcol_set, vf->field_index));
      swap_values= 1;
      break;
    }

    if (update)
    {
      int field_error __attribute__((unused)) = 0;
      /* Compute the actual value of the virtual fields */
      if (vcol_info->expr->save_in_field(vf, 0))
        field_error= error= 1;
      DBUG_PRINT("info", ("field '%s' - updated  error: %d",
                          vf->field_name, field_error));
      if (swap_values && (vf->flags & BLOB_FLAG))
      {
        /*
          Remember the read value to allow other update_virtual_field() calls
          for the same blob field for the row to be updated.
          Field_blob->read_value always contains the virtual column data for
          any read row.
        */
        ((Field_blob*) vf)->swap_value_and_read_value();
      }
    }
    else
    {
      DBUG_PRINT("info", ("field '%s' - skipped", vf->field_name));
    }
  }
  if (handler_pushed)
    in_use->pop_internal_handler();
  in_use->restore_active_arena(expr_arena, &backup_arena);
  
  /* Return 1 only of we got a fatal error, not a warning */
  DBUG_RETURN(in_use->is_error());
}

int TABLE::update_virtual_field(Field *vf)
{
  DBUG_ASSERT(!in_use->is_error());
  Query_arena backup_arena;
  DBUG_ENTER("TABLE::update_virtual_field");
  in_use->set_n_backup_active_arena(expr_arena, &backup_arena);
  bitmap_clear_all(&tmp_set);
  vf->vcol_info->expr->walk(&Item::update_vcol_processor, 0, &tmp_set);
  vf->vcol_info->expr->save_in_field(vf, 0);
  in_use->restore_active_arena(expr_arena, &backup_arena);
  DBUG_RETURN(in_use->is_error());
}


/**
  Update all DEFAULT and/or ON INSERT fields.

  @details
    Compute and set the default value of all fields with a default function.
    There are two kinds of default functions - one is used for INSERT-like
    operations, the other for UPDATE-like operations. Depending on the field
    definition and the current operation one or the other kind of update
    function is evaluated.

  @param update_command   True if command was an update else insert
  @param ignore_errors    True if we should ignore errors

  @retval
    0    Success
  @retval
    >0   Error occurred when storing a virtual field value and
         ignore_errors == 0. If set then an error was generated.
*/

int TABLE::update_default_fields(bool ignore_errors)
{
  Query_arena backup_arena;
  Field **field_ptr;
  int res= 0;
  DBUG_ENTER("TABLE::update_default_fields");
  DBUG_ASSERT(default_field);

  in_use->set_n_backup_active_arena(expr_arena, &backup_arena);

  /* Iterate over fields with default functions in the table */
  for (field_ptr= default_field; *field_ptr ; field_ptr++)
  {
    Field *field= (*field_ptr);
    /*
      If an explicit default value for a field overrides the default,
      do not update the field with its automatic default value.
    */
    if (!field->has_explicit_value())
    {
      if (field->default_value &&
          (field->default_value->flags || field->flags & BLOB_FLAG))
        res|= (field->default_value->expr->save_in_field(field, 0) < 0);
      if (!ignore_errors && res)
      {
        my_error(ER_CALCULATING_DEFAULT_VALUE, MYF(0), field->field_name);
        break;
      }
      res= 0;
    }
  }
  in_use->restore_active_arena(expr_arena, &backup_arena);
  DBUG_RETURN(res);
}

void TABLE::evaluate_update_default_function()
{
  DBUG_ENTER("TABLE::evaluate_update_default_function");

  if (s->has_update_default_function)
    for (Field **field_ptr= default_field; *field_ptr ; field_ptr++)
    {
      Field *field= (*field_ptr);
      if (!field->has_explicit_value() && field->has_update_default_function())
        field->set_time();
    }
  DBUG_VOID_RETURN;
}


/**
   Reset markers that fields are being updated
*/

void TABLE::reset_default_fields()
{
  DBUG_ENTER("reset_default_fields");
  bitmap_clear_all(&has_value_set);
  DBUG_VOID_RETURN;
}

/*
  Prepare triggers  for INSERT-like statement.

  SYNOPSIS
    prepare_triggers_for_insert_stmt_or_event()

  NOTE
    Prepare triggers for INSERT-like statement by marking fields
    used by triggers and inform handlers that batching of UPDATE/DELETE 
    cannot be done if there are BEFORE UPDATE/DELETE triggers.
*/

void TABLE::prepare_triggers_for_insert_stmt_or_event()
{
  if (triggers)
  {
    if (triggers->has_triggers(TRG_EVENT_DELETE,
                               TRG_ACTION_AFTER))
    {
      /*
        The table has AFTER DELETE triggers that might access to
        subject table and therefore might need delete to be done
        immediately. So we turn-off the batching.
      */
      (void) file->extra(HA_EXTRA_DELETE_CANNOT_BATCH);
    }
    if (triggers->has_triggers(TRG_EVENT_UPDATE,
                               TRG_ACTION_AFTER))
    {
      /*
        The table has AFTER UPDATE triggers that might access to subject
        table and therefore might need update to be done immediately.
        So we turn-off the batching.
      */
      (void) file->extra(HA_EXTRA_UPDATE_CANNOT_BATCH);
    }
  }
}


bool TABLE::prepare_triggers_for_delete_stmt_or_event()
{
  if (triggers &&
      triggers->has_triggers(TRG_EVENT_DELETE,
                             TRG_ACTION_AFTER))
  {
    /*
      The table has AFTER DELETE triggers that might access to subject table
      and therefore might need delete to be done immediately. So we turn-off
      the batching.
    */
    (void) file->extra(HA_EXTRA_DELETE_CANNOT_BATCH);
    return TRUE;
  }
  return FALSE;
}


bool TABLE::prepare_triggers_for_update_stmt_or_event()
{
  if (triggers &&
      triggers->has_triggers(TRG_EVENT_UPDATE,
                             TRG_ACTION_AFTER))
  {
    /*
      The table has AFTER UPDATE triggers that might access to subject
      table and therefore might need update to be done immediately.
      So we turn-off the batching.
    */ 
    (void) file->extra(HA_EXTRA_UPDATE_CANNOT_BATCH);
    return TRUE;
  }
  return FALSE;
}


/**
  Validates default value of fields which are not specified in
  the column list of INSERT/LOAD statement.

  @Note s->default_values should be properly populated
        before calling this function.

  @param thd              thread context
  @param record           the record to check values in

  @return
    @retval false Success.
    @retval true  Failure.
*/

bool TABLE::validate_default_values_of_unset_fields(THD *thd) const
{
  DBUG_ENTER("TABLE::validate_default_values_of_unset_fields");
  for (Field **fld= field; *fld; fld++)
  {
    if (!bitmap_is_set(write_set, (*fld)->field_index) &&
        !((*fld)->flags & NO_DEFAULT_VALUE_FLAG))
    {
      if (!(*fld)->is_null_in_record(s->default_values) &&
          (*fld)->validate_value_in_record_with_warn(thd, s->default_values) &&
          thd->is_error())
      {
        /*
          We're here if:
          - validate_value_in_record_with_warn() failed and
            strict mo validate_default_values_of_unset_fieldsde converted WARN to ERROR
          - or the connection was killed, or closed unexpectedly
        */
        DBUG_RETURN(true);
      }
    }
  }
  DBUG_RETURN(false);
}


bool TABLE::insert_all_rows_into_tmp_table(THD *thd,
                                           TABLE *tmp_table,
                                           TMP_TABLE_PARAM *tmp_table_param,
                                           bool with_cleanup)
{
  int write_err= 0;

  DBUG_ENTER("TABLE::insert_all_rows_into_tmp_table");

  if (with_cleanup)
  {
   if ((write_err= tmp_table->file->ha_delete_all_rows()))
      goto err;
  }
   
  if (file->indexes_are_disabled())
    tmp_table->file->ha_disable_indexes(HA_KEY_SWITCH_ALL);
  file->ha_index_or_rnd_end();

  if (file->ha_rnd_init_with_error(1))
    DBUG_RETURN(1);

  if (tmp_table->no_rows)
    tmp_table->file->extra(HA_EXTRA_NO_ROWS);
  else
  {
    /* update table->file->stats.records */
    file->info(HA_STATUS_VARIABLE);
    tmp_table->file->ha_start_bulk_insert(file->stats.records);
  }

  while (!file->ha_rnd_next(tmp_table->record[0]))
  {
    write_err= tmp_table->file->ha_write_tmp_row(tmp_table->record[0]);
    if (write_err)
    {
      bool is_duplicate;
      if (tmp_table->file->is_fatal_error(write_err, HA_CHECK_DUP) &&
          create_internal_tmp_table_from_heap(thd, tmp_table,
                                              tmp_table_param->start_recinfo, 
                                              &tmp_table_param->recinfo,
                                              write_err, 1, &is_duplicate))
	DBUG_RETURN(1);
       
    }  
    if (thd->check_killed())
    {
      thd->send_kill_message();
      goto err_killed;
    }
  }
  if (!tmp_table->no_rows && tmp_table->file->ha_end_bulk_insert())
    goto err;
  DBUG_RETURN(0);

err:
  DBUG_PRINT("error",("Got error: %d",write_err));
  file->print_error(write_err, MYF(0));
err_killed:
  (void) file->ha_rnd_end();
  DBUG_RETURN(1);
}



/*
  @brief Reset const_table flag

  @detail
  Reset const_table flag for this table. If this table is a merged derived
  table/view the flag is recursively reseted for all tables of the underlying
  select.
*/

void TABLE_LIST::reset_const_table()
{
  table->const_table= 0;
  if (is_merged_derived())
  {
    SELECT_LEX *select_lex= get_unit()->first_select();
    TABLE_LIST *tl;
    List_iterator<TABLE_LIST> ti(select_lex->leaf_tables);
    while ((tl= ti++))
      tl->reset_const_table();
  }
}


/*
  @brief Run derived tables/view handling phases on underlying select_lex.

  @param lex    LEX for this thread
  @param phases derived tables/views handling phases to run
                (set of DT_XXX constants)
  @details
  This function runs this derived table through specified 'phases'.
  Underlying tables of this select are handled prior to this derived.
  'lex' is passed as an argument to called functions.

  @return TRUE on error
  @return FALSE ok
*/

bool TABLE_LIST::handle_derived(LEX *lex, uint phases)
{
  SELECT_LEX_UNIT *unit= get_unit();
  DBUG_ENTER("handle_derived");
  DBUG_PRINT("enter", ("phases: 0x%x", phases));

  if (unit)
  {
    if (!is_with_table_recursive_reference())
    {
      for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
        if (sl->handle_derived(lex, phases))
          DBUG_RETURN(TRUE);
    }
    if (mysql_handle_single_derived(lex, this, phases))
      DBUG_RETURN(TRUE);
  }
  DBUG_RETURN(FALSE);
}

/**
  @brief
  Return unit of this derived table/view

  @return reference to a unit  if it's a derived table/view.
  @return 0                    when it's not a derived table/view.
*/

st_select_lex_unit *TABLE_LIST::get_unit()
{
  return (view ? &view->unit : derived);
}


/**
  @brief
  Return select_lex of this derived table/view

  @return select_lex of this derived table/view.
  @return 0          when it's not a derived table.
*/

st_select_lex *TABLE_LIST::get_single_select()
{
  SELECT_LEX_UNIT *unit= get_unit();
  return (unit ? unit->first_select() : 0);
}


/**
  @brief
  Attach a join table list as a nested join to this TABLE_LIST.

  @param join_list join table list to attach

  @details
  This function wraps 'join_list' into a nested_join of this table, thus
  turning it to a nested join leaf.
*/

void TABLE_LIST::wrap_into_nested_join(List<TABLE_LIST> &join_list)
{
  TABLE_LIST *tl;
  /*
    Walk through derived table top list and set 'embedding' to point to
    the nesting table.
  */
  nested_join->join_list.empty();
  List_iterator_fast<TABLE_LIST> li(join_list);
  nested_join->join_list= join_list;
  while ((tl= li++))
  {
    tl->embedding= this;
    tl->join_list= &nested_join->join_list;
  }
}


/**
  @brief
  Initialize this derived table/view

  @param thd  Thread handle

  @details
  This function makes initial preparations of this derived table/view for
  further processing:
    if it's a derived table this function marks it either as mergeable or
      materializable
    creates temporary table for name resolution purposes
    creates field translation for mergeable derived table/view

  @return TRUE  an error occur
  @return FALSE ok
*/

bool TABLE_LIST::init_derived(THD *thd, bool init_view)
{
  SELECT_LEX *first_select= get_single_select();
  SELECT_LEX_UNIT *unit= get_unit();

  if (!unit)
    return FALSE;
  /*
    Check whether we can merge this derived table into main select.
    Depending on the result field translation will or will not
    be created.
  */
  TABLE_LIST *first_table= (TABLE_LIST *) first_select->table_list.first;
  if (first_select->table_list.elements > 1 ||
      (first_table && first_table->is_multitable()))
    set_multitable();

  unit->derived= this;
  if (init_view && !view)
  {
    /* This is all what we can do for a derived table for now. */
    set_derived();
  }

  if (!is_view())
  {
    /* A subquery might be forced to be materialized due to a side-effect. */
    if (!is_materialized_derived() && first_select->is_mergeable() &&
        optimizer_flag(thd, OPTIMIZER_SWITCH_DERIVED_MERGE) &&
        !thd->lex->can_not_use_merged() &&
        !(thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
          thd->lex->sql_command == SQLCOM_DELETE_MULTI) &&
        !is_recursive_with_table())
      set_merged_derived();
    else
      set_materialized_derived();
  }
  /*
    Derived tables/view are materialized prior to UPDATE, thus we can skip
    them from table uniqueness check
  */
  if (is_materialized_derived())
  {
    set_check_materialized();
  }

  /*
    Create field translation for mergeable derived tables/views.
    For derived tables field translation can be created only after
    unit is prepared so all '*' are get unrolled.
  */
  if (is_merged_derived())
  {
    if (is_view() ||
        (unit->prepared &&
	!(thd->lex->context_analysis_only & CONTEXT_ANALYSIS_ONLY_VIEW)))
      create_field_translation(thd);
  }

  return FALSE;
}


/**
  @brief
  Retrieve number of rows in the table

  @details
  Retrieve number of rows in the table referred by this TABLE_LIST and
  store it in the table's stats.records variable. If this TABLE_LIST refers
  to a materialized derived table/view then the estimated number of rows of
  the derived table/view is used instead.

  @return 0          ok
  @return non zero   error
*/

int TABLE_LIST::fetch_number_of_rows()
{
  int error= 0;
  if (jtbm_subselect)
  {
    if (jtbm_subselect->is_jtbm_merged)
    {
      table->file->stats.records= (ha_rows)jtbm_subselect->jtbm_record_count;
      set_if_bigger(table->file->stats.records, 2);
      table->used_stat_records= table->file->stats.records;
    }
    return 0;
  }
  if (is_materialized_derived() && !fill_me)

  {
    table->file->stats.records= ((select_union*)derived->result)->records;
    set_if_bigger(table->file->stats.records, 2);
    table->used_stat_records= table->file->stats.records;
  }
  else
    error= table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
  return error;
}

/*
  Procedure of keys generation for result tables of materialized derived
  tables/views.

  A key is generated for each equi-join pair derived table-another table.
  Each generated key consists of fields of derived table used in equi-join.
  Example:

    SELECT * FROM (SELECT * FROM t1 GROUP BY 1) tt JOIN
                  t1 ON tt.f1=t1.f3 and tt.f2.=t1.f4;
  In this case for the derived table tt one key will be generated. It will
  consist of two parts f1 and f2.
  Example:

    SELECT * FROM (SELECT * FROM t1 GROUP BY 1) tt JOIN
                  t1 ON tt.f1=t1.f3 JOIN
                  t2 ON tt.f2=t2.f4;
  In this case for the derived table tt two keys will be generated.
  One key over f1 field, and another key over f2 field.
  Currently optimizer may choose to use only one such key, thus the second
  one will be dropped after range optimizer is finished.
  See also JOIN::drop_unused_derived_keys function.
  Example:

    SELECT * FROM (SELECT * FROM t1 GROUP BY 1) tt JOIN
                  t1 ON tt.f1=a_function(t1.f3);
  In this case for the derived table tt one key will be generated. It will
  consist of one field - f1.
*/



/*
  @brief
  Change references to underlying items of a merged derived table/view
  for fields in derived table's result table.

  @return FALSE ok
  @return TRUE  Out of memory
*/
bool TABLE_LIST::change_refs_to_fields()
{
  List_iterator<Item> li(used_items);
  Item_direct_ref *ref;
  Field_iterator_view field_it;
  THD *thd= table->in_use;
  DBUG_ASSERT(is_merged_derived());

  if (!used_items.elements)
    return FALSE;

  materialized_items= (Item**)thd->calloc(sizeof(void*) * table->s->fields);

  while ((ref= (Item_direct_ref*)li++))
  {
    uint idx;
    Item *orig_item= *ref->ref;
    field_it.set(this);
    for (idx= 0; !field_it.end_of_fields(); field_it.next(), idx++)
    {
      if (field_it.item() == orig_item)
        break;
    }
    DBUG_ASSERT(!field_it.end_of_fields());
    if (!materialized_items[idx])
    {
      materialized_items[idx]= new (thd->mem_root) Item_field(thd, table->field[idx]);
      if (!materialized_items[idx])
        return TRUE;
    }
    /*
      We need to restore the pointers after the execution of the
      prepared statement.
    */
    thd->change_item_tree((Item **)&ref->ref,
                          (Item*)(materialized_items + idx));
  }

  return FALSE;
}


void TABLE_LIST::set_lock_type(THD *thd, enum thr_lock_type lock)
{
  if (check_stack_overrun(thd, STACK_MIN_SIZE, (uchar *)&lock))
    return;
  /* we call it only when table is opened and it is "leaf" table*/
  DBUG_ASSERT(table);
  lock_type= lock;
  /* table->file->get_table() can be 0 for derived tables */
  if (table->file && table->file->get_table())
    table->file->set_lock_type(lock);
  if (is_merged_derived())
  {
    for (TABLE_LIST *table= get_single_select()->get_table_list();
         table;
         table= table->next_local)
    {
      table->set_lock_type(thd, lock);
    }
  }
}

bool TABLE_LIST::is_with_table()
{
  return derived && derived->with_element;
}


uint TABLE_SHARE::actual_n_key_parts(THD *thd)
{
  return use_ext_keys &&
         optimizer_flag(thd, OPTIMIZER_SWITCH_EXTENDED_KEYS) ?
           ext_key_parts : key_parts;
}  


double KEY::actual_rec_per_key(uint i)
{ 
  if (rec_per_key == 0)
    return 0;
  return (is_statistics_from_stat_tables ?
          read_stats->get_avg_frequency(i) : (double) rec_per_key[i]);
}


/**
  @brief
  Mark subformulas of a condition unusable for the condition pushed into table
  
  @param cond The condition whose subformulas are to be marked
  
  @details
    This method recursively traverses the AND-OR condition cond and for each subformula
    of the codition it checks whether it can be usable for the extraction of a condition
    that can be pushed into this table. The subformulas that are not usable are
    marked with the flag NO_EXTRACTION_FL.
  @note
    This method is called before any call of TABLE_LIST::build_pushable_cond_for_table.
    The flag NO_EXTRACTION_FL set in a subformula allows to avoid building clone
    for the subformula when extracting the pushable condition.
*/ 

void TABLE_LIST::check_pushable_cond_for_table(Item *cond)
{
  table_map tab_map= table->map;
  cond->clear_extraction_flag();
  if (cond->type() == Item::COND_ITEM)
  {
    bool and_cond= ((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC;
    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
    uint count= 0;
    Item *item;
    while ((item=li++))
    {
      check_pushable_cond_for_table(item);
      if (item->get_extraction_flag() !=  NO_EXTRACTION_FL)
        count++;
      else if (!and_cond)
        break;
    }
    if ((and_cond && count == 0) || item)
    {
      cond->set_extraction_flag(NO_EXTRACTION_FL);
      if (and_cond)
        li.rewind();
      while ((item= li++))
        item->clear_extraction_flag();
    }
  }
  else if (!cond->excl_dep_on_table(tab_map))
    cond->set_extraction_flag(NO_EXTRACTION_FL);
}


/**
  @brief
  Build condition extractable from the given one depended only on this table
 
  @param thd   The thread handle
  @param cond  The condition from which the pushable one is to be extracted
  
  @details
    For the given condition cond this method finds out what condition depended
    only  on this table can be extracted from cond. If such condition C exists
    the method builds the item for it.
    The method uses the flag NO_EXTRACTION_FL set by the preliminary call of
    the method TABLE_LIST::check_pushable_cond_for_table to figure out whether
    a subformula depends only on this table or not.
  @note
    The built condition C is always implied by the condition cond
    (cond => C). The method tries to build the most restictive such
    condition (i.e. for any other condition C' such that cond => C'
    we have C => C').
   @note
    The build item is not ready for usage: substitution for the field items
    has to be done and it has to be re-fixed.
 
 @retval
    the built condition pushable into this table if such a condition exists
    NULL if there is no such a condition
*/ 

Item* TABLE_LIST::build_pushable_cond_for_table(THD *thd, Item *cond) 
{
  table_map tab_map= table->map;
  bool is_multiple_equality= cond->type() == Item::FUNC_ITEM && 
  ((Item_func*) cond)->functype() == Item_func::MULT_EQUAL_FUNC;
  if (cond->get_extraction_flag() == NO_EXTRACTION_FL)
    return 0;
  if (cond->type() == Item::COND_ITEM)
  {
    bool cond_and= false;
    Item_cond *new_cond;
    if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
    {
      cond_and= true;
      new_cond=new (thd->mem_root) Item_cond_and(thd);
    }
    else
      new_cond= new (thd->mem_root) Item_cond_or(thd);
    if (!new_cond)
      return 0;		
    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
    Item *item;
    bool is_fix_needed= false;
    while ((item=li++))
    {
      if (item->get_extraction_flag() == NO_EXTRACTION_FL)
      {
	if (!cond_and)
	  return 0;
	continue;
      }
      Item *fix= build_pushable_cond_for_table(thd, item);
      if (!fix && !cond_and)
	return 0;
      if (!fix) 
	continue;

      if (fix->type() == Item::COND_ITEM &&
          ((Item_cond*) fix)->functype() == Item_func::COND_AND_FUNC)
	is_fix_needed= true;

      new_cond->argument_list()->push_back(fix, thd->mem_root);
    }
    if (is_fix_needed && new_cond->fix_fields(thd, 0))
      return 0;

    switch (new_cond->argument_list()->elements) 
    {
    case 0:
      return 0;			
    case 1:
      return new_cond->argument_list()->head();
    default:
      return new_cond;
    }
  }
  else if (is_multiple_equality)
  {
    if (!(cond->used_tables() & tab_map))
      return 0;
    Item *new_cond= NULL;
    int i= 0;
    Item_equal *item_equal= (Item_equal *) cond;
    Item *left_item = item_equal->get_const();
    Item_equal_fields_iterator it(*item_equal);
    Item *item;
    if (!left_item)
    {
      while ((item=it++))
      if (item->used_tables() == tab_map)
      {
        left_item= item;
        break;
      }
    }
    if (!left_item)
      return 0;
    while ((item=it++))
    {
      if (!(item->used_tables() == tab_map))
	continue;
      Item_func_eq *eq= 0;
      Item *left_item_clone= left_item->build_clone(thd, thd->mem_root);
      Item *right_item_clone= item->build_clone(thd, thd->mem_root);
      if (left_item_clone && right_item_clone)
      {
        left_item_clone->set_item_equal(NULL);
        right_item_clone->set_item_equal(NULL);
	eq= new (thd->mem_root) Item_func_eq(thd, right_item_clone,
                                         left_item_clone);
      }
      if (eq)
      {
	i++;
	switch (i)
	{
	case 1:
	  new_cond= eq;
	  break;
	case 2:
	  new_cond= new (thd->mem_root) Item_cond_and(thd, new_cond, eq);
	  break;
	default:
	  ((Item_cond_and*)new_cond)->argument_list()->push_back(eq,
                                                                 thd->mem_root);
	}
      }
    }
    if (new_cond)
      new_cond->fix_fields(thd, &new_cond);
    return new_cond;
  }
  else if (cond->get_extraction_flag() != NO_EXTRACTION_FL)
    return cond->build_clone(thd, thd->mem_root);
  return 0;
}

LEX_CSTRING *fk_option_name(enum_fk_option opt)
{
  static LEX_CSTRING names[]=
  {
    { STRING_WITH_LEN("???") },
    { STRING_WITH_LEN("RESTRICT") },
    { STRING_WITH_LEN("CASCADE") },
    { STRING_WITH_LEN("SET NULL") },
    { STRING_WITH_LEN("NO ACTION") },
    { STRING_WITH_LEN("SET DEFAULT") }
  };
  return names + opt;
}

bool fk_modifies_child(enum_fk_option opt)
{
  static bool can_write[]= { false, false, true, true, false, true };
  return can_write[opt];
}


/*
  @brief
    Initialize all the quick structures that are used to stored the
    estimates when the range optimizer is run.
  @details
    This is specifically needed when we read the TABLE structure from the
    table cache. There can be some garbage data from previous queries
    that need to be reset here.
*/

void TABLE::initialize_quick_structures()
{
  bzero(quick_rows, sizeof(quick_rows));
  bzero(quick_key_parts, sizeof(quick_key_parts));
  bzero(quick_costs, sizeof(quick_costs));
  bzero(quick_n_ranges, sizeof(quick_n_ranges));
}