Current File : //usr/include/mysql/server/private/filesort.h
/* Copyright (c) 2006, 2010, 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, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
#ifndef FILESORT_INCLUDED
#define FILESORT_INCLUDED
#include "my_base.h" /* ha_rows */
#include "sql_alloc.h"
#include "filesort_utils.h"
class SQL_SELECT;
class THD;
struct TABLE;
class Filesort_tracker;
struct SORT_FIELD;
typedef struct st_order ORDER;
class JOIN;
/**
Sorting related info.
To be extended by another WL to include complete filesort implementation.
*/
class Filesort: public Sql_alloc
{
public:
/** List of expressions to order the table by */
ORDER *order;
/** Number of records to return */
ha_rows limit;
/** ORDER BY list with some precalculated info for filesort */
SORT_FIELD *sortorder;
/** select to use for getting records */
SQL_SELECT *select;
/** TRUE <=> free select on destruction */
bool own_select;
/** true means we are using Priority Queue for order by with limit. */
bool using_pq;
/*
TRUE means sort operation must produce table rowids.
FALSE means that it halso has an option of producing {sort_key,
addon_fields} pairs.
*/
bool sort_positions;
Filesort_tracker *tracker;
Filesort(ORDER *order_arg, ha_rows limit_arg, bool sort_positions_arg,
SQL_SELECT *select_arg):
order(order_arg),
limit(limit_arg),
sortorder(NULL),
select(select_arg),
own_select(false),
using_pq(false),
sort_positions(sort_positions_arg)
{
DBUG_ASSERT(order);
};
~Filesort() { cleanup(); }
/* Prepare ORDER BY list for sorting. */
uint make_sortorder(THD *thd, JOIN *join, table_map first_table_bit);
private:
void cleanup();
};
class SORT_INFO
{
/// Buffer for sorting keys.
Filesort_buffer filesort_buffer;
public:
SORT_INFO()
:addon_field(0), record_pointers(0)
{
buffpek.str= 0;
my_b_clear(&io_cache);
}
~SORT_INFO();
void free_data()
{
close_cached_file(&io_cache);
my_free(record_pointers);
my_free(buffpek.str);
my_free(addon_field);
}
void reset()
{
free_data();
record_pointers= 0;
buffpek.str= 0;
addon_field= 0;
}
IO_CACHE io_cache; /* If sorted through filesort */
LEX_STRING buffpek; /* Buffer for buffpek structures */
LEX_STRING addon_buf; /* Pointer to a buffer if sorted with fields */
struct st_sort_addon_field *addon_field; /* Pointer to the fields info */
/* To unpack back */
void (*unpack)(struct st_sort_addon_field *, uchar *, uchar *);
uchar *record_pointers; /* If sorted in memory */
/*
How many rows in final result.
Also how many rows in record_pointers, if used
*/
ha_rows return_rows;
ha_rows examined_rows; /* How many rows read */
ha_rows found_rows; /* How many rows was accepted */
/** Sort filesort_buffer */
void sort_buffer(Sort_param *param, uint count)
{ filesort_buffer.sort_buffer(param, count); }
/**
Accessors for Filesort_buffer (which @c).
*/
uchar *get_record_buffer(uint idx)
{ return filesort_buffer.get_record_buffer(idx); }
uchar **get_sort_keys()
{ return filesort_buffer.get_sort_keys(); }
uchar **alloc_sort_buffer(uint num_records, uint record_length)
{ return filesort_buffer.alloc_sort_buffer(num_records, record_length); }
void free_sort_buffer()
{ filesort_buffer.free_sort_buffer(); }
void init_record_pointers()
{ filesort_buffer.init_record_pointers(); }
size_t sort_buffer_size() const
{ return filesort_buffer.sort_buffer_size(); }
friend SORT_INFO *filesort(THD *thd, TABLE *table, Filesort *filesort,
Filesort_tracker* tracker, JOIN *join,
table_map first_table_bit);
};
SORT_INFO *filesort(THD *thd, TABLE *table, Filesort *filesort,
Filesort_tracker* tracker, JOIN *join=NULL,
table_map first_table_bit=0);
void change_double_for_sort(double nr,uchar *to);
#endif /* FILESORT_INCLUDED */
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