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f52bf92014
This task deals with packing the non-sorted fields (or addon fields).
This would lead to efficient usage of the memory allocated for the sort buffer.
The changes brought by this feature are
1) Sort buffers would have records of variable length
2) Each record in the sort buffer would be stored like
<sort_key1><sort_key2>....<addon_length><null_bytes><field1><field2>....
addon_length is the extra bytes that are required to store the variable
length of addon field across different records.
3) Changes in rr_unpack_from_buffer and rr_from_tempfile to take into account
the variable length of records.
Ported WL#1509 Pack values of non-sorted fields in the sort buffer from
MySQL by Tor Didriksen
102 lines
3 KiB
C++
102 lines
3 KiB
C++
#ifndef SQL_RECORDS_H
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#define SQL_RECORDS_H
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/* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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#ifdef USE_PRAGMA_INTERFACE
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#pragma interface /* gcc class implementation */
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#endif
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#include "table.h"
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struct st_join_table;
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class handler;
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class THD;
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class SQL_SELECT;
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class Copy_field;
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class SORT_INFO;
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struct READ_RECORD;
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void end_read_record(READ_RECORD *info);
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/**
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A context for reading through a single table using a chosen access method:
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index read, scan, etc, use of cache, etc.
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Use by:
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READ_RECORD read_record;
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init_read_record(&read_record, ...);
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while (read_record.read_record())
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{
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...
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}
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end_read_record();
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*/
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struct READ_RECORD
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{
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typedef int (*Read_func)(READ_RECORD*);
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typedef void (*Unlock_row_func)(st_join_table *);
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typedef int (*Setup_func)(struct st_join_table*);
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TABLE *table; /* Head-form */
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Unlock_row_func unlock_row;
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Read_func read_record_func;
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THD *thd;
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SQL_SELECT *select;
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uint ref_length, reclength, rec_cache_size, error_offset;
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/**
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Counting records when reading result from filesort().
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Used when filesort leaves the result in the filesort buffer.
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*/
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ha_rows unpack_counter;
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uchar *ref_pos; /* pointer to form->refpos */
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uchar *rec_buf; /* to read field values after filesort */
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uchar *cache,*cache_pos,*cache_end,*read_positions;
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/*
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Structure storing information about sorting
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*/
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SORT_INFO *sort_info;
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struct st_io_cache *io_cache;
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bool print_error;
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int read_record() { return read_record_func(this); }
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uchar *record() const { return table->record[0]; }
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/*
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SJ-Materialization runtime may need to read fields from the materialized
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table and unpack them into original table fields:
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*/
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Copy_field *copy_field;
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Copy_field *copy_field_end;
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public:
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READ_RECORD() : table(NULL), cache(NULL) {}
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~READ_RECORD() { end_read_record(this); }
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};
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bool init_read_record(READ_RECORD *info, THD *thd, TABLE *reg_form,
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SQL_SELECT *select, SORT_INFO *sort,
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int use_record_cache,
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bool print_errors, bool disable_rr_cache);
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bool init_read_record_idx(READ_RECORD *info, THD *thd, TABLE *table,
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bool print_error, uint idx, bool reverse);
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void rr_unlock_row(st_join_table *tab);
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#endif /* SQL_RECORDS_H */
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