/* 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" #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) { 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])) { 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, keyinfo, 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]); /* 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 */