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f95b5b0a5d
1. Fix index access costs for MERGE tables, set block_size=myisam_block_size/#underlying_tables instead of 0 which it was before. 2. Make index scans on MERGE table to return records in (key_tuple, merge_table_rowid) order, instead of just (key_tuple) order. This makes an index scan on MERGE table to be truly a ROR-scan which is a requirement for index_merge union/intersection.
79 lines
2.4 KiB
C
79 lines
2.4 KiB
C
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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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; either version 2 of the License, or
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(at your option) any later version.
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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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include "myrg_def.h"
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static int queue_key_cmp(void *keyseg, byte *a, byte *b)
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{
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MYRG_TABLE *ma= (MYRG_TABLE *)a;
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MYRG_TABLE *mb= (MYRG_TABLE *)b;
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MI_INFO *aa= ma->table;
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MI_INFO *bb= mb->table;
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uint not_used[2];
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int ret= ha_key_cmp((HA_KEYSEG *)keyseg, aa->lastkey, bb->lastkey,
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USE_WHOLE_KEY, SEARCH_FIND, not_used);
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if (ret < 0)
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return -1;
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if (ret > 0)
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return 1;
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/*
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If index tuples have the same values, let the record with least rowid
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value be "smaller", so index scans return records ordered by (keytuple,
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rowid). This is used by index_merge access method, grep for ROR in
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sql/opt_range.cc for details.
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*/
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return (ma->file_offset < mb->file_offset)? -1 : (ma->file_offset >
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mb->file_offset) ? 1 : 0;
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} /* queue_key_cmp */
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int _myrg_init_queue(MYRG_INFO *info,int inx,enum ha_rkey_function search_flag)
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{
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int error=0;
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QUEUE *q= &(info->by_key);
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if (inx < (int) info->keys)
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{
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if (!is_queue_inited(q))
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{
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if (init_queue(q,info->tables, 0,
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(myisam_readnext_vec[search_flag] == SEARCH_SMALLER),
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queue_key_cmp,
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info->open_tables->table->s->keyinfo[inx].seg))
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error=my_errno;
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}
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else
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{
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if (reinit_queue(q,info->tables, 0,
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(myisam_readnext_vec[search_flag] == SEARCH_SMALLER),
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queue_key_cmp,
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info->open_tables->table->s->keyinfo[inx].seg))
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error=my_errno;
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}
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}
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return error;
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}
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int _myrg_mi_read_record(MI_INFO *info, byte *buf)
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{
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if (!(*info->read_record)(info,info->lastpos,buf))
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{
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info->update|= HA_STATE_AKTIV; /* Record is read */
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return 0;
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}
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return my_errno;
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}
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