mysql5/mysql-5.7.27/sql/records.h

89 lines
2.7 KiB
C++

#ifndef SQL_RECORDS_H
#define SQL_RECORDS_H
/* Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
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,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */
#include <my_global.h> /* for uint typedefs */
#include "my_base.h"
class QEP_TAB;
class handler;
struct TABLE;
class THD;
/**
A context for reading through a single table using a chosen access method:
index read, scan, etc, use of cache, etc.
Use by:
@code
READ_RECORD read_record;
if (init_read_record(&read_record, ...))
return TRUE;
while (read_record.read_record())
{
...
}
end_read_record();
@endcode
*/
class QUICK_SELECT_I;
struct READ_RECORD
{
typedef int (*Read_func)(READ_RECORD*);
typedef void (*Unlock_row_func)(QEP_TAB *);
typedef int (*Setup_func)(QEP_TAB*);
TABLE *table; /* Head-form */
TABLE **forms; /* head and ref forms */
Unlock_row_func unlock_row;
Read_func read_record;
THD *thd;
QUICK_SELECT_I *quick;
uint cache_records;
uint ref_length,struct_length,reclength,rec_cache_size,error_offset;
/**
Counting records when reading result from filesort().
Used when filesort leaves the result in the filesort buffer.
*/
ha_rows unpack_counter;
uchar *ref_pos; /* pointer to form->refpos */
uchar *record;
uchar *rec_buf; /* to read field values after filesort */
uchar *cache,*cache_pos,*cache_end,*read_positions;
struct st_io_cache *io_cache;
bool print_error, ignore_not_found_rows;
public:
READ_RECORD() { memset(this, 0, sizeof(*this)); }
};
bool init_read_record(READ_RECORD *info, THD *thd,
TABLE *table, QEP_TAB *qep_tab,
int use_record_cache,
bool print_errors, bool disable_rr_cache);
bool init_read_record_idx(READ_RECORD *info, THD *thd, TABLE *table,
bool print_error, uint idx, bool reverse);
void end_read_record(READ_RECORD *info);
void rr_unlock_row(QEP_TAB *tab);
int rr_sequential(READ_RECORD *info);
#endif /* SQL_RECORDS_H */