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/*
Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
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 St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "myisamdef.h"
#include "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 mi_rnext(MI_INFO *info, uchar *buf, int inx)
{
int error,changed;
uint flag;
uint update_mask= HA_STATE_NEXT_FOUND;
DBUG_ENTER("mi_rnext");
if ((inx = _mi_check_index(info,inx)) < 0)
DBUG_RETURN(my_errno);
flag=SEARCH_BIGGER; /* Read next */
if (info->lastpos == HA_OFFSET_ERROR && info->update & HA_STATE_PREV_FOUND)
flag=0; /* Read first */
if (fast_mi_readinfo(info))
DBUG_RETURN(my_errno);
if (info->s->concurrent_insert)
rw_rdlock(&info->s->key_root_lock[inx]);
changed=_mi_test_if_changed(info);
if (!flag)
{
switch(info->s->keyinfo[inx].key_alg){
#ifdef HAVE_RTREE_KEYS
case HA_KEY_ALG_RTREE:
error=rtree_get_first(info,inx,info->lastkey_length);
break;
#endif
case HA_KEY_ALG_BTREE:
default:
error=_mi_search_first(info,info->s->keyinfo+inx,
info->s->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 preceeding 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 (info->s->keyinfo[inx].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= rtree_get_next(info,inx,info->lastkey_length);
break;
#endif
case HA_KEY_ALG_BTREE:
default:
if (!changed)
error= _mi_search_next(info,info->s->keyinfo+inx,info->lastkey,
info->lastkey_length,flag,
info->s->state.key_root[inx]);
else
error= _mi_search(info,info->s->keyinfo+inx,info->lastkey,
USE_WHOLE_KEY,flag, info->s->state.key_root[inx]);
}
}
if (info->s->concurrent_insert)
{
if (!error)
{
while (info->lastpos >= info->state->data_file_length)
{
/* Skip rows inserted by other threads since we got a lock */
if ((error=_mi_search_next(info,info->s->keyinfo+inx,
info->lastkey,
info->lastkey_length,
SEARCH_BIGGER,
info->s->state.key_root[inx])))
break;
}
}
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|= update_mask;
if (error)
{
if (my_errno == HA_ERR_KEY_NOT_FOUND)
my_errno=HA_ERR_END_OF_FILE;
}
else if (!buf)
{
DBUG_RETURN(info->lastpos==HA_OFFSET_ERROR ? my_errno : 0);
}
else if (!(*info->read_record)(info,info->lastpos,buf))
{
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);
} /* mi_rnext */
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