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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; either version 2 of the License, or
(at your option) any later version.
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 */
#include "myisamdef.h"
/* Read a record using key */
/* Ordinary search_flag is 0 ; Give error if no record with key */
int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len,
enum ha_rkey_function search_flag)
{
uchar *key_buff;
MYISAM_SHARE *share=info->s;
uint pack_key_length;
DBUG_ENTER("mi_rkey");
DBUG_PRINT("enter",("base: %lx inx: %d search_flag: %d",
info,inx,search_flag));
if ((inx = _mi_check_index(info,inx)) < 0)
DBUG_RETURN(my_errno);
info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
if (key_len == 0)
key_len=USE_WHOLE_KEY;
key_buff=info->lastkey+info->s->base.max_key_length;
pack_key_length=_mi_pack_key(info,(uint) inx,key_buff,(uchar*) key,key_len);
info->last_rkey_length=pack_key_length;
DBUG_EXECUTE("key",_mi_print_key(DBUG_FILE,share->keyinfo[inx].seg,
key_buff,pack_key_length););
if (_mi_readinfo(info,F_RDLCK,1))
goto err;
if (share->concurrent_insert)
rw_rdlock(&share->key_root_lock[inx]);
if (!_mi_search(info,info->s->keyinfo+inx,key_buff,pack_key_length,
myisam_read_vec[search_flag],info->s->state.key_root[inx]))
{
while (info->lastpos >= info->state->data_file_length)
{
/*
Skip rows that are inserted by other threads since we got a lock
Note that this can only happen if we are not searching after an
exact key, because the keys are sorted according to position
*/
if (_mi_search_next(info,info->s->keyinfo+inx,info->lastkey,
info->lastkey_length,
myisam_readnext_vec[search_flag],
info->s->state.key_root[inx]))
break;
}
}
if (share->concurrent_insert)
rw_unlock(&share->key_root_lock[inx]);
if (!(*info->read_record)(info,info->lastpos,buf))
{
info->update|= HA_STATE_AKTIV; /* Record is read */
DBUG_RETURN(0);
}
info->lastpos = HA_OFFSET_ERROR; /* Didn't find key */
/* Store key for read next */
memcpy(info->lastkey,key_buff,pack_key_length);
bzero((char*) info->lastkey+pack_key_length,info->s->base.rec_reflength);
info->lastkey_length=pack_key_length+info->s->base.rec_reflength;
if (search_flag == HA_READ_AFTER_KEY)
info->update|=HA_STATE_NEXT_FOUND; /* Previous gives last row */
err:
DBUG_RETURN(my_errno);
} /* mi_rkey */
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