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Fix duplicating ROOT page in concurrent updates.

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This commit is contained in:
Vadim B. Mikheev
1999-04-22 08:19:59 +00:00
parent 00fbb64bed
commit 3888b53a58
2 changed files with 41 additions and 16 deletions
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41
src/backend/access/nbtree/nbtpage.c
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@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtpage.c,v 1.19 1999/03/28 20:31:57 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtpage.c,v 1.20 1999/04/22 08:19:59 vadim Exp $
*
* NOTES
* Postgres btree pages look like ordinary relation pages. The opaque
@@ -494,24 +494,37 @@ _bt_getstackbuf(Relation rel, BTStack stack, int access)
opaque = (BTPageOpaque) PageGetSpecialPointer(page);
maxoff = PageGetMaxOffsetNumber(page);
if (maxoff >= stack->bts_offset)
if (stack->bts_offset == InvalidOffsetNumber ||
maxoff >= stack->bts_offset)
{
itemid = PageGetItemId(page, stack->bts_offset);
item = (BTItem) PageGetItem(page, itemid);
/* if the item is where we left it, we're done */
if (BTItemSame(item, stack->bts_btitem))
/*
* _bt_insertonpg set bts_offset to InvalidOffsetNumber
* in the case of concurrent ROOT page split
*/
if (stack->bts_offset == InvalidOffsetNumber)
{
pfree(stack->bts_btitem);
item_nbytes = ItemIdGetLength(itemid);
item_save = (BTItem) palloc(item_nbytes);
memmove((char *) item_save, (char *) item, item_nbytes);
stack->bts_btitem = item_save;
return buf;
i = P_RIGHTMOST(opaque) ? P_HIKEY : P_FIRSTKEY;
}
else
{
itemid = PageGetItemId(page, stack->bts_offset);
item = (BTItem) PageGetItem(page, itemid);
/* if the item is where we left it, we're done */
if (BTItemSame(item, stack->bts_btitem))
{
pfree(stack->bts_btitem);
item_nbytes = ItemIdGetLength(itemid);
item_save = (BTItem) palloc(item_nbytes);
memmove((char *) item_save, (char *) item, item_nbytes);
stack->bts_btitem = item_save;
return buf;
}
i = OffsetNumberNext(stack->bts_offset);
}
/* if the item has just moved right on this page, we're done */
for (i = OffsetNumberNext(stack->bts_offset);
for ( ;
i <= maxoff;
i = OffsetNumberNext(i))
{