path: root/sql/sql_select.h

/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB

   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; either version 2 of the License, or
   (at your option) any later version.

   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */


/* classes to use when handling where clause */

#ifdef __GNUC__
#pragma interface			/* gcc class implementation */
#endif

#include "procedure.h"
#include <myisam.h>

typedef struct keyuse_t {
  TABLE *table;
  Item	*val;				/* or value if no field */
  uint	key,keypart;
  table_map used_tables;
} KEYUSE;

class store_key;

typedef struct st_table_ref
{
  bool		key_err;
  uint          key_parts;                // num of ...
  uint          key_length;               // length of key_buff
  int           key;                      // key no
  byte          *key_buff;                // value to look for with key
  byte          *key_buff2;               // key_buff+key_length
  store_key     **key_copy;               //
  Item          **items;                  // val()'s for each keypart
  table_map	depend_map;		  // Table depends on these tables.
} TABLE_REF;

/*
** CACHE_FIELD and JOIN_CACHE is used on full join to cache records in outer
** table
*/


typedef struct st_cache_field {
  char *str;
  uint length,blob_length;
  Field_blob *blob_field;
  bool strip;
} CACHE_FIELD;


typedef struct st_join_cache {
  uchar *buff,*pos,*end;
  uint records,record_nr,ptr_record,fields,length,blobs;
  CACHE_FIELD *field,**blob_ptr;
  SQL_SELECT *select;
} JOIN_CACHE;


/*
** The structs which holds the join connections and join states
*/

enum join_type { JT_UNKNOWN,JT_SYSTEM,JT_CONST,JT_EQ_REF,JT_REF,JT_MAYBE_REF,
		 JT_ALL, JT_RANGE, JT_NEXT, JT_FT};

class JOIN;

typedef struct st_join_table {
  TABLE		*table;
  KEYUSE	*keyuse;			/* pointer to first used key */
  SQL_SELECT	*select;
  COND		*select_cond;
  QUICK_SELECT	*quick;
  Item		*on_expr;
  const char	*info;
  int		(*read_first_record)(struct st_join_table *tab);
  int		(*next_select)(JOIN *,struct st_join_table *,bool);
  READ_RECORD	read_record;
  double	worst_seeks;
  key_map	const_keys;			/* Keys with constant part */
  key_map	checked_keys;			/* Keys checked in find_best */
  key_map	needed_reg;
  ha_rows	records,found_records,read_time;
  table_map	dependent,key_dependent;
  uint		keys;				/* all keys with can be used */
  uint		use_quick,index;
  uint		status;				// Save status for cache
  uint		used_fields,used_fieldlength,used_blobs;
  enum join_type type;
  bool		cached_eq_ref_table,eq_ref_table,not_used_in_distinct;
  TABLE_REF	ref;
  JOIN_CACHE	cache;
  JOIN		*join;
} JOIN_TAB;


typedef struct st_position {			/* Used in find_best */
  double records_read;
  JOIN_TAB *table;
  KEYUSE *key;
} POSITION;


/* Param to create temporary tables when doing SELECT:s */

class TMP_TABLE_PARAM :public Sql_alloc
{
 public:
  List<Item> copy_funcs;
  List_iterator_fast<Item> copy_funcs_it;
  Copy_field *copy_field, *copy_field_end;
  byte	    *group_buff;
  Item_result_field **funcs;
  MI_COLUMNDEF *recinfo,*start_recinfo;
  KEY *keyinfo;
  ha_rows end_write_records;
  uint	field_count,sum_func_count,func_count;
  uint  hidden_field_count;
  uint	group_parts,group_length,group_null_parts;
  uint	quick_group;
  bool  using_indirect_summary_function;

  TMP_TABLE_PARAM()
    :copy_funcs_it(copy_funcs), copy_field(0), group_parts(0),
    group_length(0), group_null_parts(0)
  {}
  ~TMP_TABLE_PARAM()
  {
    cleanup();
  }
  inline void cleanup(void)
  {
    if (copy_field)				/* Fix for Intel compiler */
    {
      delete [] copy_field;
      copy_field=0;
    }
  }
};

class JOIN :public Sql_alloc
{
 public:
  JOIN_TAB *join_tab,**best_ref,**map2table;
  TABLE    **table,**all_tables,*sort_by_table;
  uint	   tables,const_tables;
  uint	   send_group_parts;
  bool	   sort_and_group,first_record,full_join,group, no_field_update;
  bool	   do_send_rows;
  table_map const_table_map,found_const_table_map,outer_join;
  ha_rows  send_records,found_records,examined_rows,row_limit, select_limit;
  POSITION positions[MAX_TABLES+1],best_positions[MAX_TABLES+1];
  double   best_read;
  List<Item> *fields;
  List<Item_buff> group_fields;
  TABLE    *tmp_table;
  THD	   *thd;
  Item_sum  **sum_funcs;
  Procedure *procedure;
  Item	    *having;
  uint	    select_options;
  select_result *result;
  TMP_TABLE_PARAM tmp_table_param;
  MYSQL_LOCK *lock;
  // unit structure (with global parameters) for this select
  SELECT_LEX_UNIT *unit;
  // select that processed
  SELECT_LEX *select_lex;

  bool select_distinct, //Is select distinct?
    no_order, simple_order, simple_group,
    skip_sort_order, need_tmp,
    hidden_group_fields,
    buffer_result;
  DYNAMIC_ARRAY keyuse;
  Item::cond_result cond_value;
  List<Item> all_fields;
  List<Item> & fields_list; // hold field list passed to mysql_select
  int error;

  ORDER *order, *group_list, *proc_param; //hold parameters of mysql_select
  COND *conds;                            // ---"---
  TABLE_LIST *tables_list;           //hold 'tables' parameter of mysql_selec
  SQL_SELECT *select;                //created in optimisation phase
  TABLE      *exec_tmp_table;        //used in 'exec' to hold temporary

  const char *zero_result_cause; // not 0 if exec must return zero result
  
  my_bool union_part; // this subselect is part of union 

  JOIN(THD *thd, List<Item> &fields,
       ulong select_options, select_result *result):
    join_tab(0),
    table(0),
    tables(0), const_tables(0),
    sort_and_group(0), first_record(0),
    do_send_rows(1),
    send_records(0), found_records(0), examined_rows(0),
    thd(thd),
    sum_funcs(0),
    procedure(0),
    having(0),
    select_options(select_options),
    result(result),
    lock(thd->lock),
    select_lex(0), //for safety
    select_distinct(test(select_options & SELECT_DISTINCT)),
    no_order(0), simple_order(0), simple_group(0), skip_sort_order(0),
    need_tmp(0),
    hidden_group_fields (0), /*safety*/
    buffer_result(test(select_options & OPTION_BUFFER_RESULT) &&
		  !test(select_options & OPTION_FOUND_ROWS)),
    all_fields(fields),
    fields_list(fields),
    error(0),
    select(0),
    exec_tmp_table(0),
    zero_result_cause(0)
  {
    fields_list = fields;
    bzero((char*) &keyuse,sizeof(keyuse));
    tmp_table_param.copy_field=0;
    tmp_table_param.end_write_records= HA_POS_ERROR;
  }
  
  int prepare(TABLE_LIST *tables,
	      COND *conds, ORDER *order, ORDER *group, Item *having,
	      ORDER *proc_param, SELECT_LEX *select, SELECT_LEX_UNIT *unit,
	      bool fake_select_lex);
  int optimize();
  int global_optimize();
  int reinit();
  void exec();
  int cleanup(THD *thd);
  bool check_loop(uint id);
};


typedef struct st_select_check {
  uint const_ref,reg_ref;
} SELECT_CHECK;

extern const char *join_type_str[];
void TEST_join(JOIN *join);

/* Extern functions in sql_select.cc */
bool store_val_in_field(Field *field,Item *val);
TABLE *create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
			ORDER *group, bool distinct, bool save_sum_fields,
			ulong select_options, ha_rows rows_limit);
void free_tmp_table(THD *thd, TABLE *entry);
void count_field_types(TMP_TABLE_PARAM *param, List<Item> &fields,
		       bool reset_with_sum_func);
bool setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,List<Item> &fields);
void copy_fields(TMP_TABLE_PARAM *param);
void copy_funcs(Item_result_field **func_ptr);
bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
			     int error, bool ignore_last_dupp_error);

/* functions from opt_sum.cc */
int opt_sum_query(TABLE_LIST *tables, List<Item> &all_fields,COND *conds);


/* class to copying an field/item to a key struct */

class store_key :public Sql_alloc
{
 protected:
  Field *to_field;				// Store data here
  Field *key_field;				// Copy of key field
  char *null_ptr;
  char err;
 public:
  store_key(THD *thd, Field *field_arg, char *ptr, char *null, uint length)
    :null_ptr(null),err(0)
  {
    if (field_arg->type() == FIELD_TYPE_BLOB)
      to_field=new Field_varstring(ptr, length, (uchar*) null, 1, 
				   Field::NONE, field_arg->field_name,
				   field_arg->table, field_arg->charset());
    else
    {
      to_field=field_arg->new_field(&thd->mem_root,field_arg->table);
      if (to_field)
	to_field->move_field(ptr, (uchar*) null, 1);
    }
  }
  virtual ~store_key() {}			/* Not actually needed */
  virtual bool copy()=0;
  virtual const char *name() const=0;
};


class store_key_field: public store_key
{
  Copy_field copy_field;
  const char *field_name;
 public:
  store_key_field(THD *thd, Field *to_field_arg, char *ptr, char *null_ptr_arg,
		  uint length, Field *from_field, const char *name_arg)
    :store_key(thd, to_field_arg,ptr,
	       null_ptr_arg ? null_ptr_arg : from_field->maybe_null() ? &err
	       : NullS,length), field_name(name_arg)
  {
    if (to_field)
    {
      copy_field.set(to_field,from_field,0);
    }
  }
  bool copy()
  {
    copy_field.do_copy(&copy_field);
    return err != 0;
  }
  const char *name() const { return field_name; }
};


class store_key_item :public store_key
{
 protected:
  Item *item;
public:
  store_key_item(THD *thd, Field *to_field_arg, char *ptr, char *null_ptr_arg,
		 uint length, Item *item_arg)
    :store_key(thd, to_field_arg,ptr,
	       null_ptr_arg ? null_ptr_arg : item_arg->maybe_null ?
	       &err : NullS, length), item(item_arg)
  {}
  bool copy()
  {
    return item->save_in_field(to_field, 1) || err != 0;
  }
  const char *name() const { return "func"; }
};


class store_key_const_item :public store_key_item
{
  bool inited;
public:
  store_key_const_item(THD *thd, Field *to_field_arg, char *ptr,
		       char *null_ptr_arg, uint length,
		       Item *item_arg)
    :store_key_item(thd, to_field_arg,ptr,
		    null_ptr_arg ? null_ptr_arg : item_arg->maybe_null ?
		    &err : NullS, length, item_arg), inited(0)
  {
  }
  bool copy()
  {
    if (!inited)
    {
      inited=1;
      if (item->save_in_field(to_field, 1))
	err= 1;
    }
    return err != 0;
  }
  const char *name() const { return "const"; }
};

bool cp_buffer_from_ref(TABLE_REF *ref);
bool error_if_full_join(JOIN *join);