diff options
Diffstat (limited to 'myisam/mi_rnext_same.c')
| -rw-r--r-- | myisam/mi_rnext_same.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/myisam/mi_rnext_same.c b/myisam/mi_rnext_same.c new file mode 100644 index 00000000000..0e172894cdf --- /dev/null +++ b/myisam/mi_rnext_same.c @@ -0,0 +1,79 @@ +/* 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 */ + +#include "myisamdef.h" + + /* + Read next row with the same key as previous read, but abort if + the key changes. + One may have done a write, update or delete of the previous row. + NOTE! Even if one changes the previous row, the next read is done + based on the position of the last used key! + */ + +int mi_rnext_same(MI_INFO *info, byte *buf) +{ + int error; + uint inx,flag,not_used; + MI_KEYDEF *keyinfo; + DBUG_ENTER("mi_rnext_same"); + + if ((int) (inx=info->lastinx) < 0 || info->lastpos == HA_OFFSET_ERROR) + DBUG_RETURN(my_errno=HA_ERR_WRONG_INDEX); + keyinfo=info->s->keyinfo+inx; + flag=SEARCH_BIGGER; /* Read next */ + if (_mi_readinfo(info,F_RDLCK,1)) + DBUG_RETURN(my_errno); + + memcpy(info->lastkey2,info->lastkey,info->last_rkey_length); + if (info->s->concurrent_insert) + rw_rdlock(&info->s->key_root_lock[inx]); + for (;;) + { + if ((error=_mi_search_next(info,keyinfo,info->lastkey, + info->lastkey_length,flag, + info->s->state.key_root[inx]))) + break; + if (_mi_key_cmp(keyinfo->seg,info->lastkey2,info->lastkey, + info->last_rkey_length, SEARCH_FIND, ¬_used)) + { + error=1; + my_errno=HA_ERR_END_OF_FILE; + info->lastpos= HA_OFFSET_ERROR; + break; + } + /* Skip rows that are inserted by other threads since we got a lock */ + if (info->lastpos < info->state->data_file_length) + break; + } + if (info->s->concurrent_insert) + rw_unlock(&info->s->key_root_lock[inx]); + /* Don't clear if database-changed */ + info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED); + info->update|= HA_STATE_NEXT_FOUND; + + if (error) + { + if (my_errno == HA_ERR_KEY_NOT_FOUND) + my_errno=HA_ERR_END_OF_FILE; + } + else if (!(*info->read_record)(info,info->lastpos,buf)) + { + info->update|= HA_STATE_AKTIV; /* Record is read */ + DBUG_RETURN(0); + } + DBUG_RETURN(my_errno); +} /* mi_rnext */ |