diff options
Diffstat (limited to 'storage/myisammrg/myrg_rkey.c')
-rw-r--r-- | storage/myisammrg/myrg_rkey.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/storage/myisammrg/myrg_rkey.c b/storage/myisammrg/myrg_rkey.c new file mode 100644 index 00000000000..a85ef6a3b5e --- /dev/null +++ b/storage/myisammrg/myrg_rkey.c @@ -0,0 +1,87 @@ +/* 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 */ + +/* + * HA_READ_KEY_EXACT => SEARCH_BIGGER + * HA_READ_KEY_OR_NEXT => SEARCH_BIGGER + * HA_READ_AFTER_KEY => SEARCH_BIGGER + * HA_READ_PREFIX => SEARCH_BIGGER + * HA_READ_KEY_OR_PREV => SEARCH_SMALLER + * HA_READ_BEFORE_KEY => SEARCH_SMALLER + * HA_READ_PREFIX_LAST => SEARCH_SMALLER + */ + + +#include "myrg_def.h" + +/* todo: we could store some additional info to speedup lookups: + column (key, keyseg) can be constant per table + it can also be increasing (table1.val > table2.val > ...), + or decreasing, <=, >=, etc. + SerG +*/ + +int myrg_rkey(MYRG_INFO *info,byte *buf,int inx, const byte *key, + uint key_len, enum ha_rkey_function search_flag) +{ + byte *key_buff; + uint pack_key_length; + MYRG_TABLE *table; + MI_INFO *mi; + int err; + LINT_INIT(key_buff); + LINT_INIT(pack_key_length); + + if (_myrg_init_queue(info,inx,search_flag)) + return my_errno; + + for (table=info->open_tables ; table != info->end_table ; table++) + { + mi=table->table; + + if (table == info->open_tables) + { + err=mi_rkey(mi,0,inx,key,key_len,search_flag); + key_buff=(byte*) mi->lastkey+mi->s->base.max_key_length; + pack_key_length=mi->last_rkey_length; + } + else + { + mi->once_flags|= USE_PACKED_KEYS; + err=mi_rkey(mi,0,inx,key_buff,pack_key_length,search_flag); + } + info->last_used_table=table+1; + + if (err) + { + if (err == HA_ERR_KEY_NOT_FOUND) + continue; + return err; + } + /* adding to queue */ + queue_insert(&(info->by_key),(byte *)table); + + } + + if (!info->by_key.elements) + return HA_ERR_KEY_NOT_FOUND; + + mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table; + mi->once_flags|= RRND_PRESERVE_LASTINX; + return _myrg_mi_read_record(mi,buf); +} |