diff options
Diffstat (limited to 'storage/maria/ma_rnext_same.c')
| -rw-r--r-- | storage/maria/ma_rnext_same.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/storage/maria/ma_rnext_same.c b/storage/maria/ma_rnext_same.c new file mode 100644 index 00000000..19a950d3 --- /dev/null +++ b/storage/maria/ma_rnext_same.c @@ -0,0 +1,122 @@ +/* Copyright (C) 2006 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; 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 Street, Fifth Floor, Boston, MA 02110-1335 USA */ + +#include "maria_def.h" +#include "ma_rt_index.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 maria_rnext_same(MARIA_HA *info, uchar *buf) +{ + int error; + uint inx,not_used[2]; + MARIA_KEYDEF *keyinfo; + check_result_t check= CHECK_POS; + DBUG_ENTER("maria_rnext_same"); + + if ((int) (inx= info->lastinx) < 0 || + info->cur_row.lastpos == HA_OFFSET_ERROR) + DBUG_RETURN(my_errno=HA_ERR_WRONG_INDEX); + if (fast_ma_readinfo(info)) + DBUG_RETURN(my_errno); + + keyinfo= info->s->keyinfo+inx; + if (info->s->lock_key_trees) + mysql_rwlock_rdlock(&keyinfo->root_lock); + + switch (keyinfo->key_alg) { +#ifdef HAVE_RTREE_KEYS + case HA_KEY_ALG_RTREE: + if ((error=maria_rtree_find_next(info,inx, + maria_read_vec[info->last_key_func]))) + { + error=1; + my_errno=HA_ERR_END_OF_FILE; + info->cur_row.lastpos= HA_OFFSET_ERROR; + break; + } + break; +#endif + case HA_KEY_ALG_BTREE: + default: + if (!(info->update & HA_STATE_RNEXT_SAME)) + { + /* First rnext_same; Store old key */ + memcpy(info->lastkey_buff2, info->last_key.data, + info->last_rkey_length); + } + for (;;) + { + if ((error= _ma_search_next(info, &info->last_key, + SEARCH_BIGGER, + info->s->state.key_root[inx]))) + break; + if (ha_key_cmp(keyinfo->seg, info->last_key.data, + info->lastkey_buff2, + info->last_rkey_length, SEARCH_FIND, + not_used)) + { + error=1; + my_errno=HA_ERR_END_OF_FILE; + info->cur_row.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 && + ma_yield_and_check_if_killed(info, inx)) + { + error= 1; + break; + } + /* Skip rows that are inserted by other threads since we got a lock */ + if ((info->s->row_is_visible)(info) && + ((check= ma_check_index_cond(info, inx, buf)) != CHECK_NEG)) + break; + } + } + if (info->s->lock_key_trees) + mysql_rwlock_unlock(&keyinfo->root_lock); + /* Don't clear if database-changed */ + info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED); + info->update|= HA_STATE_NEXT_FOUND | HA_STATE_RNEXT_SAME; + + if (error || check != CHECK_POS) + { + fast_ma_writeinfo(info); + if (my_errno == HA_ERR_KEY_NOT_FOUND) + my_errno= HA_ERR_END_OF_FILE; + } + else if (!buf) + { + fast_ma_writeinfo(info); + DBUG_RETURN(info->cur_row.lastpos == HA_OFFSET_ERROR ? my_errno : 0); + } + else if (!(*info->read_record)(info, buf, info->cur_row.lastpos)) + { + info->update|= HA_STATE_AKTIV; /* Record is read */ + DBUG_RETURN(0); + } + DBUG_RETURN(my_errno); +} /* maria_rnext_same */ |