diff options
Diffstat (limited to 'myisam/mi_rkey.c')
| -rw-r--r-- | myisam/mi_rkey.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/myisam/mi_rkey.c b/myisam/mi_rkey.c new file mode 100644 index 00000000000..0b88a62e7fc --- /dev/null +++ b/myisam/mi_rkey.c @@ -0,0 +1,89 @@ +/* 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 */ |