diff options
Diffstat (limited to 'storage/myisam/mi_rkey.c')
| -rw-r--r-- | storage/myisam/mi_rkey.c | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/storage/myisam/mi_rkey.c b/storage/myisam/mi_rkey.c new file mode 100644 index 00000000..bf6f3ef8 --- /dev/null +++ b/storage/myisam/mi_rkey.c @@ -0,0 +1,265 @@ +/* Copyright (c) 2000-2007 MySQL AB, 2009 Sun Microsystems, Inc. + Use is subject to license terms. + + 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 02110-1335 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, uchar *buf, int inx, const uchar *key, + key_part_map keypart_map, 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; + check_result_t res= CHECK_NEG; + DBUG_ENTER("mi_rkey"); + DBUG_PRINT("enter", ("base: %p buf: %p inx: %d search_flag: %d", + info, 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 + In this key 'key_part_map' is the length of the key ! + */ + key_buff=info->lastkey+info->s->base.max_key_length; + pack_key_length= keypart_map; + bmove(key_buff, key, pack_key_length); + last_used_keyseg= info->s->keyinfo[inx].seg + info->last_used_keyseg; + } + else + { + DBUG_ASSERT(keypart_map); + /* 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, + keypart_map, &last_used_keyseg); + /* Save packed_key_length for use by the MERGE engine. */ + info->pack_key_length= pack_key_length; + info->last_used_keyseg= (uint16) (last_used_keyseg - + info->s->keyinfo[inx].seg); + 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) + mysql_rwlock_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; + if (share->concurrent_insert) + mysql_rwlock_unlock(&share->key_root_lock[inx]); + fast_mi_writeinfo(info); + 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])) + { + /* + Found a key, but it might not be usable. We cannot use rows that + are inserted by other threads after we got our table lock + ("concurrent inserts"). The record may not even be present yet. + Keys are inserted into the index(es) before the record is + inserted into the data file. When we got our table lock, we + saved the current data_file_length. Concurrent inserts always go + to the end of the file. So we can test if the found key + references a new record. + + If we are 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. + + We do also continue searching if an index condition check function + is available. + */ + while ((info->lastpos >= info->state->data_file_length && + (search_flag != HA_READ_KEY_EXACT || + last_used_keyseg != keyinfo->seg + keyinfo->keysegs)) || + (res= mi_check_index_tuple(info, inx, buf)) == CHECK_NEG) + { + 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])) + { + info->lastpos= HA_OFFSET_ERROR; + 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; + } + /* + If we are at the last key on the key page, allow writers to + access the index. + */ + if (info->int_keypos >= info->int_maxpos && + mi_yield_and_check_if_killed(info, inx)) + { + /* Aborted by user */ + DBUG_ASSERT(info->lastpos == HA_OFFSET_ERROR && + my_errno == HA_ERR_ABORTED_BY_USER); + res= CHECK_ERROR; + buf= 0; /* Fast abort */ + break; + } + } + if (res == CHECK_OUT_OF_RANGE) + { + /* Change error from HA_ERR_END_OF_FILE */ + DBUG_ASSERT(info->lastpos == HA_OFFSET_ERROR); + my_errno= HA_ERR_KEY_NOT_FOUND; + } + /* + Error if no row found within the data file. (Bug #29838) + Do not overwrite my_errno if already at HA_OFFSET_ERROR. + */ + if (info->lastpos != HA_OFFSET_ERROR && + info->lastpos >= info->state->data_file_length) + { + info->lastpos= HA_OFFSET_ERROR; + my_errno= HA_ERR_KEY_NOT_FOUND; + } + } + else + { + DBUG_ASSERT(info->lastpos == HA_OFFSET_ERROR); + } + } + if (share->concurrent_insert) + mysql_rwlock_unlock(&share->key_root_lock[inx]); + + info->last_rkey_length= pack_key_length; + + if (info->lastpos == HA_OFFSET_ERROR) /* No such record */ + { + fast_mi_writeinfo(info); + if (!buf) + DBUG_RETURN(my_errno); + } + else + { + /* Calculate length of the found key; Used by mi_rnext_same */ + if ((keyinfo->flag & HA_VAR_LENGTH_KEY) && last_used_keyseg) + info->last_rkey_length= _mi_keylength_part(keyinfo, info->lastkey, + last_used_keyseg); + + /* Check if we don't want to have record back, only error message */ + if (!buf) + { + fast_mi_writeinfo(info); + DBUG_RETURN(0); + } + if (!(*info->read_record)(info,info->lastpos,buf)) + { + info->update|= HA_STATE_AKTIV; /* Record is read */ + DBUG_RETURN(0); + } + DBUG_PRINT("error", ("Didn't find row. Error %d", my_errno)); + info->lastpos= HA_OFFSET_ERROR; /* Didn't find row */ + } + + /* 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 */ + + +/* + Yield to possible other writers during a index scan. + Check also if we got killed by the user and if yes, return + HA_ERR_LOCK_WAIT_TIMEOUT + + return 0 ok + return 1 Query has been requested to be killed +*/ + +my_bool mi_yield_and_check_if_killed(MI_INFO *info, int inx) +{ + MYISAM_SHARE *share; + if (mi_killed(info)) + { + /* purecov: begin tested */ + info->lastpos= HA_OFFSET_ERROR; + /* Set error that we where aborted by kill from application */ + my_errno= HA_ERR_ABORTED_BY_USER; + return 1; + /* purecov: end */ + + } + + if ((share= info->s)->concurrent_insert) + { + /* Give writers a chance to access index */ + mysql_rwlock_unlock(&share->key_root_lock[inx]); + mysql_rwlock_rdlock(&share->key_root_lock[inx]); + } + return 0; +} |