mariadb/myisam/mi_rnext_same.c
monty@mysql.com 67ce247965 Add support for up to VARCHAR (size up to 65535)
Renamed HA_VAR_LENGTH to HA_VAR_LENGTH_PART
Renamed in all files FIELD_TYPE_STRING and FIELD_TYPE_VAR_STRING to MYSQL_TYPE_STRING and MYSQL_TYPE_VAR_STRING to make it easy to catch all possible errors
Added support for VARCHAR KEYS to heap
Removed support for ISAM
Now only long VARCHAR columns are changed to TEXT on demand (not CHAR)
Internal temporary files can now use fixed length tables if the used VARCHAR columns are short
2004-12-06 02:00:37 +02:00

101 lines
3.1 KiB
C

/* 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"
#include "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 mi_rnext_same(MI_INFO *info, byte *buf)
{
int error;
uint inx,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;
if (fast_mi_readinfo(info))
DBUG_RETURN(my_errno);
if (info->s->concurrent_insert)
rw_rdlock(&info->s->key_root_lock[inx]);
switch (keyinfo->key_alg)
{
#ifdef HAVE_RTREE_KEYS
case HA_KEY_ALG_RTREE:
if ((error=rtree_find_next(info,inx,
myisam_read_vec[info->last_key_func])))
{
error=1;
my_errno=HA_ERR_END_OF_FILE;
info->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->lastkey2,info->lastkey,info->last_rkey_length);
}
for (;;)
{
if ((error=_mi_search_next(info,keyinfo,info->lastkey,
info->lastkey_length,SEARCH_BIGGER,
info->s->state.key_root[inx])))
break;
if (ha_key_cmp(keyinfo->seg,info->lastkey2,info->lastkey,
info->last_rkey_length, SEARCH_FIND, &not_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 | HA_STATE_RNEXT_SAME;
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 */