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Diffstat (limited to 'src/backend/storage/buffer/bufmgr.c')
-rw-r--r--src/backend/storage/buffer/bufmgr.c20
1 files changed, 19 insertions, 1 deletions
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 1f6e8d36803..4a7dda3edbb 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.249 2009/03/23 01:52:38 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.250 2009/03/31 22:12:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -122,6 +122,12 @@ PrefetchBuffer(Relation reln, ForkNumber forkNum, BlockNumber blockNum)
if (reln->rd_istemp)
{
+ /* see comments in ReadBufferExtended */
+ if (RELATION_IS_OTHER_TEMP(reln))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot access temporary tables of other sessions")));
+
/* pass it off to localbuf.c */
LocalPrefetchBuffer(reln->rd_smgr, forkNum, blockNum);
}
@@ -205,6 +211,16 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
RelationOpenSmgr(reln);
/*
+ * Reject attempts to read non-local temporary relations; we would
+ * be likely to get wrong data since we have no visibility into the
+ * owning session's local buffers.
+ */
+ if (RELATION_IS_OTHER_TEMP(reln))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot access temporary tables of other sessions")));
+
+ /*
* Read the buffer, and update pgstat counters to reflect a cache
* hit or miss.
*/
@@ -220,6 +236,8 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
/*
* ReadBufferWithoutRelcache -- like ReadBufferExtended, but doesn't require
* a relcache entry for the relation.
+ *
+ * NB: caller is assumed to know what it's doing if isTemp is true.
*/
Buffer
ReadBufferWithoutRelcache(RelFileNode rnode, bool isTemp,