Need defense against oversize index entries in btree CREATE INDEX,

as well as when inserting entries into an existing index.
This commit is contained in:
Tom Lane 2000-01-08 21:24:49 +00:00
parent 8da88a6f2b
commit b79e75d66f
1 changed files with 18 additions and 1 deletions

View File

@ -27,7 +27,7 @@
* Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsort.c,v 1.47 1999/10/17 22:15:04 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtsort.c,v 1.48 2000/01/08 21:24:49 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -301,6 +301,23 @@ _bt_buildadd(Relation index, BTPageState *state, BTItem bti, int flags)
pgspc = PageGetFreeSpace(npage);
btisz = BTITEMSZ(bti);
btisz = MAXALIGN(btisz);
/*
* Check whether the item can fit on a btree page at all.
* (Eventually, we ought to try to apply TOAST methods if not.)
* We actually need to be able to fit three items on every page,
* so restrict any one item to 1/3 the per-page available space.
* Note that at this point, btisz doesn't include the ItemId.
*
* NOTE: similar code appears in _bt_insertonpg() to defend against
* oversize items being inserted into an already-existing index.
* But during creation of an index, we don't go through there.
*/
if (btisz > (PageGetPageSize(npage)-sizeof(PageHeaderData)-MAXALIGN(sizeof(BTPageOpaqueData)))/3 - sizeof(ItemIdData))
elog(ERROR, "btree: index item size %d exceeds maximum %d",
btisz,
(PageGetPageSize(npage)-sizeof(PageHeaderData)-MAXALIGN(sizeof(BTPageOpaqueData)))/3 - sizeof(ItemIdData));
if (pgspc < btisz)
{
Buffer obuf = nbuf;