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Fixed (I hope) unique btree index implementation.

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This commit is contained in:
Vadim B. Mikheev 1997-01-10 10:06:20 +00:00
parent c6a605705c
commit daec84f09d
1 changed files with 88 additions and 26 deletions
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114
src/backend/access/nbtree/nbtinsert.c
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@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.8 1996/12/06 09:45:30 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.9 1997/01/10 10:06:20 vadim Exp $
*
*-------------------------------------------------------------------------
*/
@ -17,6 +17,7 @@
#include <utils/memutils.h>
#include <storage/bufpage.h>
#include <access/nbtree.h>
#include <access/heapam.h>
#include <storage/bufmgr.h>
#ifndef HAVE_MEMMOVE
@ -41,7 +42,7 @@ static void _bt_updateitem(Relation rel, Size keysz, Buffer buf, Oid bti_oid, BT
* (xid, seqno) pair.
*/
InsertIndexResult
_bt_doinsert(Relation rel, BTItem btitem, bool index_is_unique, bool is_update)
_bt_doinsert(Relation rel, BTItem btitem, bool index_is_unique, Relation heapRel)
{
ScanKey itup_scankey;
IndexTuple itup;
@ -60,30 +61,6 @@ _bt_doinsert(Relation rel, BTItem btitem, bool index_is_unique, bool is_update)
/* find the page containing this key */
stack = _bt_search(rel, natts, itup_scankey, &buf);
/* if we're not allowing duplicates, make sure the key isn't */
/* already in the node */
if(index_is_unique && !is_update) {
OffsetNumber offset;
TupleDesc itupdesc;
Page page;
itupdesc = RelationGetTupleDescriptor(rel);
page = BufferGetPage(buf);
offset = _bt_binsrch(rel, buf, natts, itup_scankey, BT_DESCENT);
/* make sure the offset we're given points to an actual */
/* key on the page before trying to compare it */
if(!PageIsEmpty(page) &&
offset <= PageGetMaxOffsetNumber(page)) {
if(!_bt_compare(rel, itupdesc, page,
natts, itup_scankey, offset)) {
/* it is a duplicate */
elog(WARN, "Cannot insert a duplicate key into a unique index.");
}
}
}
blkno = BufferGetBlockNumber(buf);
/* trade in our read lock for a write lock */
@ -100,6 +77,91 @@ _bt_doinsert(Relation rel, BTItem btitem, bool index_is_unique, bool is_update)
buf = _bt_moveright(rel, buf, natts, itup_scankey, BT_WRITE);
/* if we're not allowing duplicates, make sure the key isn't */
/* already in the node */
if ( index_is_unique )
{
OffsetNumber offset, maxoff;
Page page;
page = BufferGetPage(buf);
maxoff = PageGetMaxOffsetNumber (page);
offset = _bt_binsrch(rel, buf, natts, itup_scankey, BT_DESCENT);
/* make sure the offset we're given points to an actual */
/* key on the page before trying to compare it */
if ( !PageIsEmpty (page) && offset <= maxoff )
{
TupleDesc itupdesc;
BTItem btitem;
IndexTuple itup;
HeapTuple htup;
BTPageOpaque opaque;
Buffer nbuf;
BlockNumber blkno;
itupdesc = RelationGetTupleDescriptor(rel);
nbuf = InvalidBuffer;
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
while ( !_bt_compare (rel, itupdesc, page,
natts, itup_scankey, offset) )
{ /* they're equal */
btitem = (BTItem) PageGetItem(page, PageGetItemId(page, offset));
itup = &(btitem->bti_itup);
htup = heap_fetch (heapRel, SelfTimeQual, &(itup->t_tid), NULL);
if ( htup != (HeapTuple) NULL )
{ /* it is a duplicate */
elog(WARN, "Cannot insert a duplicate key into a unique index.");
}
/* get next offnum */
if ( offset < maxoff )
{
offset = OffsetNumberNext(offset);
}
else
{ /* move right ? */
if ( P_RIGHTMOST (opaque) )
break;
if ( _bt_compare (rel, itupdesc, page,
natts, itup_scankey, P_HIKEY) )
break;
/*
* min key of the right page is the same,
* ooh - so many dead duplicates...
*/
blkno = opaque->btpo_next;
if ( nbuf != InvalidBuffer )
_bt_relbuf (rel, nbuf, BT_READ);
for (nbuf = InvalidBuffer; ; )
{
nbuf = _bt_getbuf (rel, blkno, BT_READ);
page = BufferGetPage (nbuf);
maxoff = PageGetMaxOffsetNumber(page);
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
offset = P_RIGHTMOST(opaque) ? P_HIKEY : P_FIRSTKEY;
if ( ! PageIsEmpty (page) && offset <= maxoff )
{ /* Found some key */
break;
}
else
{ /* Empty or "pseudo"-empty page - get next */
blkno = opaque->btpo_next;
_bt_relbuf (rel, nbuf, BT_READ);
nbuf = InvalidBuffer;
if ( blkno == P_NONE )
break;
}
}
if ( nbuf == InvalidBuffer )
break;
}
}
if ( nbuf != InvalidBuffer )
_bt_relbuf(rel, nbuf, BT_READ);
}
}
/* do the insertion */
res = _bt_insertonpg(rel, buf, stack, natts, itup_scankey,
btitem, (BTItem) NULL);