MDEV-10139 Support for SEQUENCE objects

Working features:
CREATE OR REPLACE [TEMPORARY] SEQUENCE [IF NOT EXISTS] name
    [ INCREMENT [ BY | = ] increment ]
    [ MINVALUE [=] minvalue | NO MINVALUE ]
    [ MAXVALUE [=] maxvalue | NO MAXVALUE ]
    [ START [ WITH | = ] start ] [ CACHE [=] cache ] [ [ NO ] CYCLE ]
    ENGINE=xxx COMMENT=".."
SELECT NEXT VALUE FOR sequence_name;
SELECT NEXTVAL(sequence_name);
SELECT PREVIOUS VALUE FOR sequence_name;
SELECT LASTVAL(sequence_name);

SHOW CREATE SEQUENCE sequence_name;
SHOW CREATE TABLE sequence_name;
CREATE TABLE sequence-structure ... SEQUENCE=1
ALTER TABLE sequence RENAME TO sequence2;
RENAME TABLE sequence TO sequence2;
DROP [TEMPORARY] SEQUENCE  [IF EXISTS] sequence_names

Missing features
- SETVAL(value,sequence_name), to be used with replication.
- Check replication, including checking that sequence tables are marked
  not transactional.
- Check that a commit happens for NEXT VALUE that changes table data (may
  already work)
- ALTER SEQUENCE. ANSI SQL version of setval.
- Share identical sequence entries to not add things twice to table list.
- testing insert/delete/update/truncate/load data
- Run and fix Alibaba sequence tests (part of mysql-test/suite/sql_sequence)
- Write documentation for NEXT VALUE / PREVIOUS_VALUE
- NEXTVAL in DEFAULT
  - Ensure that NEXTVAL in DEFAULT uses database from base table
- Two NEXTVAL for same row should give same answer.
- Oracle syntax sequence_table.nextval, without any FOR or FROM.
- Sequence tables are treated as 'not read constant tables' by SELECT; Would
  be better if we would have a separate list for sequence tables so that
  select doesn't know about them, except if refereed to with FROM.

Other things done:
- Improved output for safemalloc backtrack
- frm_type_enum changed to Table_type
- Removed lex->is_view and replaced with lex->table_type. This allows
  use to more easy check if item is view, sequence or table.
- Added table flag HA_CAN_TABLES_WITHOUT_ROLLBACK, needed for handlers
  that want's to support sequences
- Added handler calls:
 - engine_name(), to simplify getting engine name for partition and sequences
 - update_first_row(), to be able to do efficient sequence implementations.
 - Made binlog_log_row() global to be able to call it from ha_sequence.cc
- Added handler variable: row_already_logged, to be able to flag that the
  changed row is already logging to replication log.
- Added CF_DB_CHANGE and CF_SCHEMA_CHANGE flags to simplify
  deny_updates_if_read_only_option()
- Added sp_add_cfetch() to avoid new conflicts in sql_yacc.yy
- Moved code for add_table_options() out from sql_show.cc::show_create_table()
- Added String::append_longlong() and used it in sql_show.cc to simplify code.
- Added extra option to dd_frm_type() and ha_table_exists to indicate if
  the table is a sequence. Needed by DROP SQUENCE to not drop a table.

1 files changed, 417 insertions, 0 deletions

diff --git a/sql/ha_sequence.cc b/sql/ha_sequence.cc
new file mode 100644
index 00000000000..f3c4d8961a8
--- /dev/null
+++ b/sql/ha_sequence.cc
@@ -0,0 +1,417 @@
+/*
+   Copyright (c) 2017, Aliyun and/or its affiliates.
+   Copyright (c) 2017, MariaDB corporation
+
+   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 St, Fifth Floor, Boston, MA 02110-1301  USA
+*/
+
+#include <my_global.h>
+#include "sql_list.h"
+#include "table.h"
+#include "sql_sequence.h"
+#include "ha_sequence.h"
+#include "sql_plugin.h"
+#include "mysql/plugin.h"
+#include "sql_priv.h"
+#include "sql_parse.h"
+#include "sql_table.h"
+#include "sql_update.h"
+#include "sql_base.h"
+#include "log_event.h"
+
+/*
+  Table flags we should inherit and disable from the original engine.
+  We add HA_STATS_RECORDS_IS_EXACT as ha_sequence::info() will ensure
+  that records is always 1
+*/
+
+#define SEQUENCE_ENABLED_TABLE_FLAGS  (HA_STATS_RECORDS_IS_EXACT | \
+                                       HA_PERSISTENT_TABLE)
+#define SEQUENCE_DISABLED_TABLE_FLAGS  (HA_CAN_SQL_HANDLER | \
+                                        HA_CAN_INSERT_DELAYED | \
+                                        HA_BINLOG_STMT_CAPABLE)
+handlerton *sql_sequence_hton;
+
+/*
+  Create a sequence handler
+*/
+
+ha_sequence::ha_sequence(handlerton *hton, TABLE_SHARE *share)
+  :handler(hton, share), sequence_locked(0)
+{
+  sequence= share->sequence;
+  DBUG_ASSERT(share->sequence);
+}
+
+/**
+   Destructor method must remove the underlying handler
+*/
+ha_sequence::~ha_sequence()
+{
+  delete file;
+}
+
+/**
+   Sequence table open method
+
+   @param name            Path to file (dbname and tablename)
+   @param mode            mode
+   @param flags           Flags how to open file
+
+   RETURN VALUES
+   @retval 0              Success
+   @retval != 0           Failure
+*/
+
+int ha_sequence::open(const char *name, int mode, uint flags)
+{
+  int error;
+  DBUG_ENTER("ha_sequence::open");
+  DBUG_ASSERT(table->s == table_share && file);
+
+  file->table= table;
+  if (!(error= file->open(name, mode, flags)))
+  {
+    /*
+      Copy values set by handler::open() in the underlying handler
+      Reuse original storage engine data for duplicate key reference
+      It would be easier to do this if we would have another handler
+      call:  fixup_after_open()...
+    */
+    ref=        file->ref;
+    ref_length= file->ref_length;
+    dup_ref=    file->dup_ref;
+
+    /*
+      ha_open() sets the following for us. We have to set this for the
+      underlying handler
+    */
+    file->cached_table_flags= file->table_flags();
+
+    file->reset_statistics();
+    internal_tmp_table= file->internal_tmp_table=
+      MY_TEST(flags & HA_OPEN_INTERNAL_TABLE);
+    reset_statistics();
+
+    /* Don't try to read the inital row the call is part of create code */
+    if (!(flags & (HA_OPEN_FOR_CREATE | HA_OPEN_FOR_REPAIR)))
+    {
+      if ((error= table->s->sequence->read_initial_values(table)))
+        file->ha_close();
+    }
+  }
+  DBUG_RETURN(error);
+}
+
+/*
+  Clone the sequence. Needed if table is used by range optimization
+  (Very, very unlikely)
+*/
+
+handler *ha_sequence::clone(const char *name, MEM_ROOT *mem_root)
+{
+  ha_sequence *new_handler;
+  DBUG_ENTER("ha_sequence::clone");
+  if (!(new_handler= new (mem_root) ha_sequence(ht, table_share)))
+    DBUG_RETURN(NULL);
+
+  /*
+    Allocate new_handler->ref here because otherwise ha_open will allocate it
+    on this->table->mem_root and we will not be able to reclaim that memory
+    when the clone handler object is destroyed.
+  */
+
+  if (!(new_handler->ref= (uchar*) alloc_root(mem_root,
+                                              ALIGN_SIZE(ref_length)*2)))
+    goto err;
+
+  if (new_handler->ha_open(table, name,
+                           table->db_stat,
+                           HA_OPEN_IGNORE_IF_LOCKED | HA_OPEN_NO_PSI_CALL))
+    goto err;
+
+  /* Reuse original storage engine data for duplicate key reference */
+  new_handler->ref=        file->ref;
+  new_handler->ref_length= file->ref_length;
+  new_handler->dup_ref=    file->dup_ref;
+
+  DBUG_RETURN((handler*) new_handler);
+
+err:
+  delete new_handler;
+  DBUG_RETURN(NULL);
+}
+
+
+/*
+  Map the create table to the original storage engine
+*/
+
+int ha_sequence::create(const char *name, TABLE *form,
+                        HA_CREATE_INFO *create_info)
+{
+  DBUG_ASSERT(create_info->sequence);
+  /* Sequence tables has one and only one row */
+  create_info->max_rows= create_info->min_rows= 1;
+  return (file->create(name, form, create_info));
+}
+
+/**
+  Sequence write row method.
+
+  A sequence table has only one row. Any inserts in the table
+  will update this row.
+
+  @retval 0     Success
+  @retval != 0  Failure
+
+  NOTES:
+    sequence_locked is set if we are called from SEQUENCE::next_value
+    In this case the mutex is already locked and we should not update
+    the sequence with 'buf' as the sequence object is already up to date.
+*/
+
+int ha_sequence::write_row(uchar *buf)
+{
+  int error;
+  DBUG_ENTER("ha_sequence::write_row");
+  DBUG_ASSERT(table->record[0] == buf);
+
+  row_already_logged= 0;
+  if (!sequence->initialized)
+  {
+    /* This calls is from ha_open() as part of create table */
+    DBUG_RETURN(file->write_row(buf));
+  }
+
+  /*
+    User tries to write a row
+    - Check that row is an accurate object
+    - Update the first row in the table
+  */
+
+  sequence_definition tmp_seq;
+  tmp_seq.read_fields(table);
+  if (tmp_seq.check_and_adjust())
+    DBUG_RETURN(HA_ERR_SEQUENCE_INVALID_DATA);
+
+  /*
+    Lock sequence to ensure that no one can come in between
+    while sequence, table and binary log are updated.
+  */
+  if (!sequence_locked)                         // If not from next_value()
+    sequence->lock();
+
+  if (!(error= file->update_first_row(buf)))
+  {
+    Log_func *log_func= Write_rows_log_event::binlog_row_logging_function;
+    if (!sequence_locked)
+      sequence->copy(&tmp_seq);
+    rows_changed++;
+    /* We have to do the logging while we hold the sequence mutex */
+    error= binlog_log_row(table, 0, buf, log_func);
+    row_already_logged= 1;
+  }
+
+  sequence->all_values_used= 0;
+  if (!sequence_locked)
+    sequence->unlock();
+  DBUG_RETURN(error);
+}
+
+
+int ha_sequence::update_row(const uchar *old_data, uchar *new_data)
+{
+  int error;
+  sequence_definition tmp_seq;
+  DBUG_ENTER("ha_sequence::update_row");
+  DBUG_ASSERT(new_data == table->record[0]);
+
+  row_already_logged= 0;
+
+  tmp_seq.read_fields(table);
+  if (tmp_seq.check_and_adjust())
+    DBUG_RETURN(HA_ERR_SEQUENCE_INVALID_DATA);
+
+  /*
+    Lock sequence to ensure that no one can come in between
+    while sequence, table and binary log is updated.
+  */
+  sequence->lock();
+  if (!(error= file->update_row(old_data, new_data)))
+  {
+    sequence->copy(&tmp_seq);
+    rows_changed++;
+    /* We have to do the logging while we hold the sequence mutex */
+    error= binlog_log_row(table, old_data, new_data,
+                          Update_rows_log_event::binlog_row_logging_function);
+    row_already_logged= 1;
+  }
+  sequence->all_values_used= 0;
+  sequence->unlock();
+  DBUG_RETURN(error);
+}
+
+
+/*
+  Inherit the sequence base table flags.
+*/
+
+handler::Table_flags ha_sequence::table_flags() const
+{
+  DBUG_ENTER("ha_sequence::table_flags");
+  DBUG_RETURN((file->table_flags() & ~SEQUENCE_DISABLED_TABLE_FLAGS) |
+              SEQUENCE_ENABLED_TABLE_FLAGS);
+}
+
+
+int ha_sequence::info(uint flag)
+{
+  DBUG_ENTER("ha_sequence::info");
+  file->info(flag);
+  /* Inform optimizer that we have always only one record */
+  stats= file->stats;
+  stats.records= 1;
+  DBUG_RETURN(false);
+}
+
+int ha_sequence::external_lock(THD *thd, int lock_type)
+{
+  int error= file->external_lock(thd, lock_type);
+
+  /*
+    Copy lock flag to satisfy DBUG_ASSERT checks in ha_* functions in
+    handler.cc when we later call it with file->ha_..()
+  */
+  file->m_lock_type= lock_type;
+  return error;
+}
+
+/*
+  Squence engine error deal method
+*/
+
+void ha_sequence::print_error(int error, myf errflag)
+{
+  char *sequence_db=   table_share->db.str;
+  char *sequence_name= table_share->table_name.str;
+  DBUG_ENTER("ha_sequence::print_error");
+
+  switch (error) {
+  case HA_ERR_SEQUENCE_INVALID_DATA:
+  {
+    my_error(ER_SEQUENCE_INVALID_DATA, MYF(errflag), sequence_db,
+             sequence_name);
+    DBUG_VOID_RETURN;
+  }
+  case HA_ERR_SEQUENCE_RUN_OUT:
+  {
+    my_error(ER_SEQUENCE_RUN_OUT, MYF(errflag), sequence_db, sequence_name);
+    DBUG_VOID_RETURN;
+  }
+  case HA_ERR_WRONG_COMMAND:
+    my_error(ER_ILLEGAL_HA, MYF(0), "SEQUENCE", table_share->db.str,
+             table_share->table_name.str);
+    DBUG_VOID_RETURN;
+  }
+  file->print_error(error, errflag);
+  DBUG_VOID_RETURN;
+}
+
+/*****************************************************************************
+  Sequence plugin interface
+*****************************************************************************/
+
+/*
+ Create an new handler
+*/
+
+static handler *sequence_create_handler(handlerton *hton,
+                                        TABLE_SHARE *share,
+                                        MEM_ROOT *mem_root)
+{
+  DBUG_ENTER("sequence_create_handler");
+  DBUG_RETURN(new (mem_root) ha_sequence(hton, share));
+}
+
+
+/*
+  Sequence engine end.
+
+  SYNOPSIS
+    sequence_end()
+    p                           handlerton.
+    type                        panic type.
+  RETURN VALUES
+    0           Success
+    !=0         Failure
+*/
+static int sequence_end(handlerton* hton,
+                        ha_panic_function type __attribute__((unused)))
+{
+  DBUG_ENTER("sequence_end");
+  DBUG_RETURN(0);
+}
+
+
+/*
+  Sequence engine init.
+
+  SYNOPSIS
+    sequence_initialize()
+
+    @param p    handlerton.
+
+    retval 0    Success
+    retval !=0  Failure
+*/
+
+static int sequence_initialize(void *p)
+{
+  handlerton *local_sequence_hton= (handlerton *)p;
+  DBUG_ENTER("sequence_initialize");
+
+  local_sequence_hton->state= SHOW_OPTION_YES;
+  local_sequence_hton->db_type= DB_TYPE_SEQUENCE;
+  local_sequence_hton->create= sequence_create_handler;
+  local_sequence_hton->panic= sequence_end;
+  local_sequence_hton->flags= (HTON_NOT_USER_SELECTABLE |
+                               HTON_HIDDEN |
+                               HTON_TEMPORARY_NOT_SUPPORTED |
+                               HTON_ALTER_NOT_SUPPORTED |
+                               HTON_NO_PARTITION);
+  DBUG_RETURN(0);
+}
+
+
+static struct st_mysql_storage_engine sequence_storage_engine=
+{ MYSQL_HANDLERTON_INTERFACE_VERSION };
+
+maria_declare_plugin(sql_sequence)
+{
+  MYSQL_STORAGE_ENGINE_PLUGIN,
+  &sequence_storage_engine,
+  "SQL_SEQUENCE",
+  "jianwei.zhao @ Aliyun & Monty @ MariaDB corp",
+  "Sequence Storage Engine for CREATE SEQUENCE",
+  PLUGIN_LICENSE_GPL,
+  sequence_initialize,        /* Plugin Init */
+  NULL,                       /* Plugin Deinit */
+  0x0100,                     /* 1.0 */
+  NULL,                       /* status variables                */
+  NULL,                       /* system variables                */
+  "1.0",                      /* string version                  */
+  MariaDB_PLUGIN_MATURITY_ALPHA /* maturity                     */
+}
+maria_declare_plugin_end;