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;
struct SORT_FIELD_ATTR;
typedef struct st_order ORDER;
class JOIN;
class Addon_fields;
class Sort_keys;
/**
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;
/* Used with ROWNUM. Contains the number of rows filesort has found so far */
ha_rows *accepted_rows;
/** 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 also has an option of producing {sort_key, addon_fields}
pairs.
Usually initialized with value of join_tab->keep_current_rowid to allow for
a call to table->file->position() using these table rowids.
*/
bool sort_positions;
/*
TRUE means all the fields of table of whose bitmap read_set is set
need to be read while reading records in the sort buffer.
FALSE otherwise
*/
bool set_all_read_bits;
Filesort_tracker *tracker;
Sort_keys *sort_keys;
/* Unpack temp table columns to base table columns*/
void (*unpack)(TABLE *);
Filesort(ORDER *order_arg, ha_rows limit_arg, bool sort_positions_arg,
SQL_SELECT *select_arg):
order(order_arg),
limit(limit_arg),
sortorder(NULL),
accepted_rows(0),
select(select_arg),
own_select(false),
using_pq(false),
sort_positions(sort_positions_arg),
set_all_read_bits(false),
sort_keys(NULL),
unpack(NULL)
{
DBUG_ASSERT(order);
};
~Filesort() { cleanup(); }
/* Prepare ORDER BY list for sorting. */
Sort_keys* 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_fields(NULL), record_pointers(0),
sort_keys(NULL),
sorted_result_in_fsbuf(FALSE)
{
buffpek.str= 0;
my_b_clear(&io_cache);
}
~SORT_INFO();
void free_data()
{
close_cached_file(&io_cache);
free_addon_buff();
my_free(record_pointers);
my_free(buffpek.str);
my_free(addon_fields);
free_sort_buffer();
}
void reset()
{
free_data();
record_pointers= 0;
buffpek.str= 0;
addon_fields= 0;
sorted_result_in_fsbuf= false;
}
void free_addon_buff();
IO_CACHE io_cache; /* If sorted through filesort */
LEX_STRING buffpek; /* Buffer for buffpek structures */
Addon_fields *addon_fields; /* Addon field descriptors */
uchar *record_pointers; /* If sorted in memory */
Sort_keys *sort_keys; /* Sort key descriptors*/
/**
If the entire result of filesort fits in memory, we skip the merge phase.
We may leave the result in filesort_buffer
(indicated by sorted_result_in_fsbuf), or we may strip away
the sort keys, and copy the sorted result into a new buffer.
@see save_index()
*/
bool sorted_result_in_fsbuf;
/*
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); }
uchar **get_sort_keys()
{ return filesort_buffer.get_sort_keys(); }
uchar *get_sorted_record(uint ix)
{ return filesort_buffer.get_sorted_record(ix); }
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(); }
bool isfull() const
{ return filesort_buffer.isfull(); }
void init_record_pointers()
{ filesort_buffer.init_record_pointers(); }
void init_next_record_pointer()
{ filesort_buffer.init_next_record_pointer(); }
uchar *get_next_record_pointer()
{ return filesort_buffer.get_next_record_pointer(); }
void adjust_next_record_pointer(uint val)
{ filesort_buffer.adjust_next_record_pointer(val); }
Bounds_checked_array<uchar> get_raw_buf()
{ return filesort_buffer.get_raw_buf(); }
size_t sort_buffer_size() const
{ return filesort_buffer.sort_buffer_size(); }
bool is_allocated() const
{ return filesort_buffer.is_allocated(); }
void set_sort_length(uint val)
{ filesort_buffer.set_sort_length(val); }
uint get_sort_length() const
{ return filesort_buffer.get_sort_length(); }
bool has_filesort_result_in_memory() const
{
return record_pointers || sorted_result_in_fsbuf;
}
/// Are we using "addon fields"?
bool using_addon_fields() const
{
return addon_fields != NULL;
}
/// Are we using "packed addon fields"?
bool using_packed_addons();
/**
Copies (unpacks) values appended to sorted fields from a buffer back to
their regular positions specified by the Field::ptr pointers.
@param buff Buffer which to unpack the value from
*/
template<bool Packed_addon_fields>
inline void unpack_addon_fields(uchar *buff);
bool using_packed_sortkeys();
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);
bool filesort_use_addons(TABLE *table, uint sortlength,
uint *length, uint *fields, uint *null_fields,
uint *m_packable_length);
void change_double_for_sort(double nr,uchar *to);
void store_length(uchar *to, uint length, uint pack_length);
void
reverse_key(uchar *to, const SORT_FIELD_ATTR *sort_field);
#endif /* FILESORT_INCLUDED */
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