diff options
Diffstat (limited to 'storage/maria/ma_rnext.c')
| -rw-r--r-- | storage/maria/ma_rnext.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/storage/maria/ma_rnext.c b/storage/maria/ma_rnext.c new file mode 100644 index 00000000..6fd6f891 --- /dev/null +++ b/storage/maria/ma_rnext.c @@ -0,0 +1,156 @@ +/* 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 + 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(MARIA_HA *info, uchar *buf, int inx) +{ + int error,changed; + uint flag; + MARIA_SHARE *share= info->s; + MARIA_KEYDEF *keyinfo; + check_result_t check= CHECK_POS; + uint update_mask= HA_STATE_NEXT_FOUND; + DBUG_ENTER("maria_rnext"); + + if ((inx = _ma_check_index(info,inx)) < 0) + DBUG_RETURN(my_errno); + flag=SEARCH_BIGGER; /* Read next */ + if (info->cur_row.lastpos == HA_OFFSET_ERROR && + info->update & HA_STATE_PREV_FOUND) + flag=0; /* Read first */ + + if (fast_ma_readinfo(info)) + DBUG_RETURN(my_errno); + keyinfo= share->keyinfo + inx; + if (share->lock_key_trees) + mysql_rwlock_rdlock(&keyinfo->root_lock); + changed= _ma_test_if_changed(info); + if (!flag) + { + switch (keyinfo->key_alg){ +#ifdef HAVE_RTREE_KEYS + case HA_KEY_ALG_RTREE: + error=maria_rtree_get_first(info, inx, + info->last_key.data_length + + info->last_key.ref_length); + + break; +#endif + case HA_KEY_ALG_BTREE: + default: + error= _ma_search_first(info, keyinfo, share->state.key_root[inx]); + break; + } + /* + "search first" failed. This means we have no pivot for + "search next", or in other words MI_INFO::lastkey is + likely uninitialized. + + Normally SQL layer would never request "search next" if + "search first" failed. But HANDLER may do anything. + + As mi_rnext() without preceding mi_rkey()/mi_rfirst() + equals to mi_rfirst(), we must restore original state + as if failing mi_rfirst() was not called. + */ + if (error) + update_mask|= HA_STATE_PREV_FOUND; + } + else + { + switch (keyinfo->key_alg) { +#ifdef HAVE_RTREE_KEYS + case HA_KEY_ALG_RTREE: + /* + Note that rtree doesn't support that the table + may be changed since last call, so we do need + to skip rows inserted by other threads like in btree + */ + error= maria_rtree_get_next(info, inx, info->last_key.data_length + + info->last_key.ref_length); + break; +#endif + case HA_KEY_ALG_BTREE: + default: + if (!changed) + error= _ma_search_next(info, &info->last_key, + flag | info->last_key.flag, + share->state.key_root[inx]); + else + error= _ma_search(info, &info->last_key, flag | info->last_key.flag, + share->state.key_root[inx]); + } + } + + if (!error) + { + while (!(*share->row_is_visible)(info) || + ((check= ma_check_index_cond(info, inx, buf)) == CHECK_NEG)) + { + /* + 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)) + { + /* my_errno is set by ma_yield_and_check_if_killed() */ + error= 1; + break; + } + + /* Skip rows inserted by other threads since we got a lock */ + if ((error= _ma_search_next(info, &info->last_key, + SEARCH_BIGGER, + share->state.key_root[inx]))) + break; + } + } + if (share->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|= update_mask; + + 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_PRINT("error",("Got error: %d, errno: %d",error, my_errno)); + DBUG_RETURN(my_errno); +} /* maria_rnext */ |