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/* Copyright (c) 2000, 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 02110-1301 USA */
#include "myrg_def.h"
static int queue_key_cmp(void *keyseg, uchar *a, uchar *b)
{
MYRG_TABLE *ma= (MYRG_TABLE *)a;
MYRG_TABLE *mb= (MYRG_TABLE *)b;
MI_INFO *aa= ma->table;
MI_INFO *bb= mb->table;
uint not_used[2];
int ret= ha_key_cmp((HA_KEYSEG *)keyseg, aa->lastkey, bb->lastkey,
USE_WHOLE_KEY, SEARCH_FIND, not_used);
if (ret < 0)
return -1;
if (ret > 0)
return 1;
/*
If index tuples have the same values, let the record with least rowid
value be "smaller", so index scans return records ordered by (keytuple,
rowid). This is used by index_merge access method, grep for ROR in
sql/opt_range.cc for details.
*/
return (ma->file_offset < mb->file_offset)? -1 : (ma->file_offset >
mb->file_offset) ? 1 : 0;
} /* queue_key_cmp */
int _myrg_init_queue(MYRG_INFO *info,int inx,enum ha_rkey_function search_flag)
{
int error=0;
QUEUE *q= &(info->by_key);
if (inx < (int) info->keys)
{
if (!is_queue_inited(q))
{
if (init_queue(q,info->tables, 0,
(myisam_readnext_vec[search_flag] == SEARCH_SMALLER),
queue_key_cmp,
info->open_tables->table->s->keyinfo[inx].seg, 0, 0))
error=my_errno;
}
else
{
if (reinit_queue(q,info->tables, 0,
(myisam_readnext_vec[search_flag] == SEARCH_SMALLER),
queue_key_cmp,
info->open_tables->table->s->keyinfo[inx].seg, 0, 0))
error=my_errno;
}
}
else
{
/*
inx may be bigger than info->keys if there are no underlying tables
defined. In this case we should return empty result. As we check for
underlying tables conformance when we open a table, we may not enter
this branch with underlying table that has less keys than merge table
have.
*/
DBUG_ASSERT(!info->tables);
error= my_errno= HA_ERR_END_OF_FILE;
}
return error;
}
int _myrg_mi_read_record(MI_INFO *info, uchar *buf)
{
if (!(*info->read_record)(info,info->lastpos,buf))
{
info->update|= HA_STATE_AKTIV; /* Record is read */
return 0;
}
return my_errno;
}
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