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/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* Read record based on a key */
/*
* HA_READ_KEY_EXACT => SEARCH_BIGGER
* HA_READ_KEY_OR_NEXT => SEARCH_BIGGER
* HA_READ_AFTER_KEY => SEARCH_BIGGER
* HA_READ_PREFIX => SEARCH_BIGGER
* HA_READ_KEY_OR_PREV => SEARCH_SMALLER
* HA_READ_BEFORE_KEY => SEARCH_SMALLER
* HA_READ_PREFIX_LAST => SEARCH_SMALLER
*/
#include "myrg_def.h"
/* todo: we could store some additional info to speedup lookups:
column (key, keyseg) can be constant per table
it can also be increasing (table1.val > table2.val > ...),
or decreasing, <=, >=, etc.
SerG
*/
int myrg_rkey(MYRG_INFO *info,byte *buf,int inx, const byte *key,
uint key_len, enum ha_rkey_function search_flag)
{
byte *key_buff;
uint pack_key_length;
MYRG_TABLE *table;
MI_INFO *mi;
int err;
DBUG_ENTER("myrg_rkey");
LINT_INIT(key_buff);
LINT_INIT(pack_key_length);
if (_myrg_init_queue(info,inx,search_flag))
DBUG_RETURN(my_errno);
for (table=info->open_tables ; table != info->end_table ; table++)
{
mi=table->table;
if (table == info->open_tables)
{
err=mi_rkey(mi,0,inx,key,key_len,search_flag);
/* Get the saved packed key and packed key length. */
key_buff=(byte*) mi->lastkey+mi->s->base.max_key_length;
pack_key_length=mi->pack_key_length;
}
else
{
mi->once_flags|= USE_PACKED_KEYS;
err=mi_rkey(mi,0,inx,key_buff,pack_key_length,search_flag);
}
info->last_used_table=table+1;
if (err)
{
if (err == HA_ERR_KEY_NOT_FOUND)
continue;
DBUG_PRINT("exit", ("err: %d", err));
DBUG_RETURN(err);
}
/* adding to queue */
queue_insert(&(info->by_key),(byte *)table);
}
DBUG_PRINT("info", ("tables with matches: %u", info->by_key.elements));
if (!info->by_key.elements)
DBUG_RETURN(HA_ERR_KEY_NOT_FOUND);
mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table;
mi->once_flags|= RRND_PRESERVE_LASTINX;
DBUG_PRINT("info", ("using table no: %d",
(int) (info->current_table - info->open_tables + 1)));
DBUG_DUMP("result key", (byte*) mi->lastkey, mi->lastkey_length);
DBUG_RETURN(_myrg_mi_read_record(mi,buf));
}
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