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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 */
#include "myisamdef.h"
#include "rt_index.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;
MI_KEYDEF *keyinfo;
HA_KEYSEG *last_used_keyseg;
uint pack_key_length, use_key_length, nextflag;
DBUG_ENTER("mi_rkey");
DBUG_PRINT("enter", ("base: %lx buf: %lx inx: %d search_flag: %d",
(long) info, (long) buf, inx, search_flag));
if ((inx = _mi_check_index(info,inx)) < 0)
DBUG_RETURN(my_errno);
info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
info->last_key_func= search_flag;
keyinfo= share->keyinfo + inx;
if (info->once_flags & USE_PACKED_KEYS)
{
info->once_flags&= ~USE_PACKED_KEYS; /* Reset flag */
/*
key is already packed!; This happens when we are using a MERGE TABLE
*/
key_buff=info->lastkey+info->s->base.max_key_length;
pack_key_length= key_len;
bmove(key_buff,key,key_len);
last_used_keyseg= 0;
}
else
{
if (key_len == 0)
key_len=USE_WHOLE_KEY;
/* Save the packed key for later use in the second buffer of lastkey. */
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, &last_used_keyseg);
/* Save packed_key_length for use by the MERGE engine. */
info->pack_key_length= pack_key_length;
DBUG_EXECUTE("key",_mi_print_key(DBUG_FILE, keyinfo->seg,
key_buff, pack_key_length););
}
if (fast_mi_readinfo(info))
goto err;
if (share->concurrent_insert)
rw_rdlock(&share->key_root_lock[inx]);
nextflag=myisam_read_vec[search_flag];
use_key_length=pack_key_length;
if (!(nextflag & (SEARCH_FIND | SEARCH_NO_FIND | SEARCH_LAST)))
use_key_length=USE_WHOLE_KEY;
switch (info->s->keyinfo[inx].key_alg) {
#ifdef HAVE_RTREE_KEYS
case HA_KEY_ALG_RTREE:
if (rtree_find_first(info,inx,key_buff,use_key_length,nextflag) < 0)
{
mi_print_error(info->s, HA_ERR_CRASHED);
my_errno=HA_ERR_CRASHED;
goto err;
}
break;
#endif
case HA_KEY_ALG_BTREE:
default:
if (!_mi_search(info, keyinfo, key_buff, use_key_length,
myisam_read_vec[search_flag], info->s->state.key_root[inx]))
{
/*
If we searching for a partial key (or using >, >=, < or <=) and
the data is outside of the data file, we need to continue searching
for the first key inside the data file
*/
if (info->lastpos >= info->state->data_file_length &&
(search_flag != HA_READ_KEY_EXACT ||
last_used_keyseg != keyinfo->seg + keyinfo->keysegs))
{
do
{
uint not_used[2];
/*
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
full length exact key, because the keys are sorted
according to position
*/
if (_mi_search_next(info, keyinfo, info->lastkey,
info->lastkey_length,
myisam_readnext_vec[search_flag],
info->s->state.key_root[inx]))
break;
/*
Check that the found key does still match the search.
_mi_search_next() delivers the next key regardless of its
value.
*/
if (search_flag == HA_READ_KEY_EXACT &&
ha_key_cmp(keyinfo->seg, key_buff, info->lastkey, use_key_length,
SEARCH_FIND, not_used))
{
my_errno= HA_ERR_KEY_NOT_FOUND;
info->lastpos= HA_OFFSET_ERROR;
break;
}
} while (info->lastpos >= info->state->data_file_length);
}
}
}
if (share->concurrent_insert)
rw_unlock(&share->key_root_lock[inx]);
/* Calculate length of the found key; Used by mi_rnext_same */
if ((keyinfo->flag & HA_VAR_LENGTH_KEY) && last_used_keyseg &&
info->lastpos != HA_OFFSET_ERROR)
info->last_rkey_length= _mi_keylength_part(keyinfo, info->lastkey,
last_used_keyseg);
else
info->last_rkey_length= pack_key_length;
/* Check if we don't want to have record back, only error message */
if (!buf)
DBUG_RETURN(info->lastpos == HA_OFFSET_ERROR ? my_errno : 0);
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 last used key as a base for read next */
memcpy(info->lastkey,key_buff,pack_key_length);
info->last_rkey_length= 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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