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266 lines
9 KiB
C
266 lines
9 KiB
C
/* Copyright (c) 2000-2007 MySQL AB, 2009 Sun Microsystems, Inc.
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Use is subject to license terms.
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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; version 2 of the License.
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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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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/* Read record based on a key */
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#include "myisamdef.h"
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#include "rt_index.h"
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/* Read a record using key */
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/* Ordinary search_flag is 0 ; Give error if no record with key */
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int mi_rkey(MI_INFO *info, uchar *buf, int inx, const uchar *key,
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key_part_map keypart_map, enum ha_rkey_function search_flag)
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{
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uchar *key_buff;
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MYISAM_SHARE *share=info->s;
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MI_KEYDEF *keyinfo;
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HA_KEYSEG *last_used_keyseg;
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uint pack_key_length, use_key_length, nextflag;
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ICP_RESULT res= ICP_NO_MATCH;
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DBUG_ENTER("mi_rkey");
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DBUG_PRINT("enter", ("base: 0x%lx buf: 0x%lx inx: %d search_flag: %d",
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(long) info, (long) buf, inx, search_flag));
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if ((inx = _mi_check_index(info,inx)) < 0)
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DBUG_RETURN(my_errno);
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info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
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info->last_key_func= search_flag;
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keyinfo= share->keyinfo + inx;
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if (info->once_flags & USE_PACKED_KEYS)
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{
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info->once_flags&= ~USE_PACKED_KEYS; /* Reset flag */
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/*
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key is already packed!; This happens when we are using a MERGE TABLE
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In this key 'key_part_map' is the length of the key !
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*/
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key_buff=info->lastkey+info->s->base.max_key_length;
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pack_key_length= keypart_map;
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bmove(key_buff, key, pack_key_length);
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last_used_keyseg= info->s->keyinfo[inx].seg + info->last_used_keyseg;
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}
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else
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{
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DBUG_ASSERT(keypart_map);
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/* Save the packed key for later use in the second buffer of lastkey. */
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key_buff=info->lastkey+info->s->base.max_key_length;
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pack_key_length=_mi_pack_key(info,(uint) inx, key_buff, (uchar*) key,
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keypart_map, &last_used_keyseg);
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/* Save packed_key_length for use by the MERGE engine. */
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info->pack_key_length= pack_key_length;
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info->last_used_keyseg= (uint16) (last_used_keyseg -
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info->s->keyinfo[inx].seg);
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DBUG_EXECUTE("key",_mi_print_key(DBUG_FILE, keyinfo->seg,
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key_buff, pack_key_length););
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}
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if (fast_mi_readinfo(info))
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goto err;
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if (share->concurrent_insert)
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mysql_rwlock_rdlock(&share->key_root_lock[inx]);
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nextflag=myisam_read_vec[search_flag];
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use_key_length=pack_key_length;
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if (!(nextflag & (SEARCH_FIND | SEARCH_NO_FIND | SEARCH_LAST)))
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use_key_length=USE_WHOLE_KEY;
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switch (info->s->keyinfo[inx].key_alg) {
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#ifdef HAVE_RTREE_KEYS
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case HA_KEY_ALG_RTREE:
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if (rtree_find_first(info,inx,key_buff,use_key_length,nextflag) < 0)
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{
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mi_print_error(info->s, HA_ERR_CRASHED);
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my_errno=HA_ERR_CRASHED;
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if (share->concurrent_insert)
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mysql_rwlock_unlock(&share->key_root_lock[inx]);
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fast_mi_writeinfo(info);
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goto err;
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}
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break;
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#endif
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case HA_KEY_ALG_BTREE:
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default:
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if (!_mi_search(info, keyinfo, key_buff, use_key_length,
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myisam_read_vec[search_flag], info->s->state.key_root[inx]))
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{
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/*
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Found a key, but it might not be usable. We cannot use rows that
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are inserted by other threads after we got our table lock
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("concurrent inserts"). The record may not even be present yet.
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Keys are inserted into the index(es) before the record is
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inserted into the data file. When we got our table lock, we
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saved the current data_file_length. Concurrent inserts always go
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to the end of the file. So we can test if the found key
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references a new record.
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If we are searching for a partial key (or using >, >=, < or <=) and
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the data is outside of the data file, we need to continue searching
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for the first key inside the data file.
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We do also continue searching if an index condition check function
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is available.
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*/
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while ((info->lastpos >= info->state->data_file_length &&
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(search_flag != HA_READ_KEY_EXACT ||
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last_used_keyseg != keyinfo->seg + keyinfo->keysegs)) ||
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(info->index_cond_func &&
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(res= mi_check_index_cond(info, inx, buf)) == ICP_NO_MATCH))
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{
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uint not_used[2];
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/*
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Skip rows that are inserted by other threads since we got a lock
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Note that this can only happen if we are not searching after an
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full length exact key, because the keys are sorted
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according to position
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*/
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if (_mi_search_next(info, keyinfo, info->lastkey,
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info->lastkey_length,
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myisam_readnext_vec[search_flag],
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info->s->state.key_root[inx]))
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{
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info->lastpos= HA_OFFSET_ERROR;
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break;
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}
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/*
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Check that the found key does still match the search.
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_mi_search_next() delivers the next key regardless of its
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value.
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*/
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if (search_flag == HA_READ_KEY_EXACT &&
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ha_key_cmp(keyinfo->seg, key_buff, info->lastkey, use_key_length,
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SEARCH_FIND, not_used))
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{
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my_errno= HA_ERR_KEY_NOT_FOUND;
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info->lastpos= HA_OFFSET_ERROR;
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break;
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}
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/*
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If we are at the last key on the key page, allow writers to
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access the index.
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*/
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if (info->int_keypos >= info->int_maxpos &&
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mi_yield_and_check_if_killed(info, inx))
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{
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/* Aborted by user */
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DBUG_ASSERT(info->lastpos == HA_OFFSET_ERROR &&
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my_errno == HA_ERR_ABORTED_BY_USER);
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res= ICP_ERROR;
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buf= 0; /* Fast abort */
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break;
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}
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}
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if (res == ICP_OUT_OF_RANGE)
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{
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/* Change error from HA_ERR_END_OF_FILE */
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DBUG_ASSERT(info->lastpos == HA_OFFSET_ERROR);
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my_errno= HA_ERR_KEY_NOT_FOUND;
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}
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/*
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Error if no row found within the data file. (Bug #29838)
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Do not overwrite my_errno if already at HA_OFFSET_ERROR.
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*/
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if (info->lastpos != HA_OFFSET_ERROR &&
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info->lastpos >= info->state->data_file_length)
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{
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info->lastpos= HA_OFFSET_ERROR;
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my_errno= HA_ERR_KEY_NOT_FOUND;
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}
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}
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else
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{
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DBUG_ASSERT(info->lastpos == HA_OFFSET_ERROR);
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}
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}
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if (share->concurrent_insert)
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mysql_rwlock_unlock(&share->key_root_lock[inx]);
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info->last_rkey_length= pack_key_length;
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if (info->lastpos == HA_OFFSET_ERROR) /* No such record */
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{
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fast_mi_writeinfo(info);
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if (!buf)
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DBUG_RETURN(my_errno);
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}
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else
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{
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/* Calculate length of the found key; Used by mi_rnext_same */
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if ((keyinfo->flag & HA_VAR_LENGTH_KEY) && last_used_keyseg)
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info->last_rkey_length= _mi_keylength_part(keyinfo, info->lastkey,
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last_used_keyseg);
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/* Check if we don't want to have record back, only error message */
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if (!buf)
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{
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fast_mi_writeinfo(info);
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DBUG_RETURN(0);
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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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DBUG_RETURN(0);
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}
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DBUG_PRINT("error", ("Didn't find row. Error %d", my_errno));
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info->lastpos= HA_OFFSET_ERROR; /* Didn't find row */
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}
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/* Store last used key as a base for read next */
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memcpy(info->lastkey,key_buff,pack_key_length);
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info->last_rkey_length= pack_key_length;
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bzero((char*) info->lastkey+pack_key_length,info->s->base.rec_reflength);
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info->lastkey_length=pack_key_length+info->s->base.rec_reflength;
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if (search_flag == HA_READ_AFTER_KEY)
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info->update|=HA_STATE_NEXT_FOUND; /* Previous gives last row */
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err:
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DBUG_RETURN(my_errno);
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} /* _mi_rkey */
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/*
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Yield to possible other writers during a index scan.
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Check also if we got killed by the user and if yes, return
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HA_ERR_LOCK_WAIT_TIMEOUT
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return 0 ok
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return 1 Query has been requested to be killed
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*/
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my_bool mi_yield_and_check_if_killed(MI_INFO *info, int inx)
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{
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MYISAM_SHARE *share;
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if (mi_killed(info))
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{
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/* purecov: begin tested */
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info->lastpos= HA_OFFSET_ERROR;
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/* Set error that we where aborted by kill from application */
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my_errno= HA_ERR_ABORTED_BY_USER;
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return 1;
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/* purecov: end */
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}
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if ((share= info->s)->concurrent_insert)
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{
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/* Give writers a chance to access index */
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mysql_rwlock_unlock(&share->key_root_lock[inx]);
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mysql_rwlock_rdlock(&share->key_root_lock[inx]);
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}
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return 0;
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}
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