From 03ffc4d6d5440dc7694b476854d1c63dd7dd1d6b Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 28 Nov 2007 20:44:26 +0000
Subject: [PATCH] Improve test coverage of CLOBBER_CACHE_ALWAYS by having it
also force reloading of operator class information on each use of
LookupOpclassInfo. Had this been in place a year ago, it would have helped me
find a bug in the then-new 'operator family' code. Now that we have a build
farm member testing CLOBBER_CACHE_ALWAYS on a regular basis, it seems worth
expending a little bit of effort here.
---
src/backend/utils/cache/relcache.c | 68 +++++++++++++++++++-----------
1 file changed, 44 insertions(+), 24 deletions(-)
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index e28a79134e8..d0fe1e06ac8 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.264 2007/11/15 21:14:40 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/cache/relcache.c,v 1.265 2007/11/28 20:44:26 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1133,9 +1133,13 @@ IndexSupportInitialize(oidvector *indclass,
* numbers is passed in, rather than being looked up, mainly because the
* caller will have it already.
*
- * XXX There isn't any provision for flushing the cache. However, there
- * isn't any provision for flushing relcache entries when opclass info
- * changes, either :-(
+ * Note there is no provision for flushing the cache. This is OK at the
+ * moment because there is no way to ALTER any interesting properties of an
+ * existing opclass --- all you can do is drop it, which will result in
+ * a useless but harmless dead entry in the cache. To support altering
+ * opclass membership (not the same as opfamily membership!), we'd need to
+ * be able to flush this cache as well as the contents of relcache entries
+ * for indexes.
*/
static OpClassCacheEnt *
LookupOpclassInfo(Oid operatorClassOid,
@@ -1170,34 +1174,50 @@ LookupOpclassInfo(Oid operatorClassOid,
(void *) &operatorClassOid,
HASH_ENTER, &found);
- if (found && opcentry->valid)
+ if (!found)
+ {
+ /* Need to allocate memory for new entry */
+ opcentry->valid = false; /* until known OK */
+ opcentry->numStrats = numStrats;
+ opcentry->numSupport = numSupport;
+
+ if (numStrats > 0)
+ opcentry->operatorOids = (Oid *)
+ MemoryContextAllocZero(CacheMemoryContext,
+ numStrats * sizeof(Oid));
+ else
+ opcentry->operatorOids = NULL;
+
+ if (numSupport > 0)
+ opcentry->supportProcs = (RegProcedure *)
+ MemoryContextAllocZero(CacheMemoryContext,
+ numSupport * sizeof(RegProcedure));
+ else
+ opcentry->supportProcs = NULL;
+ }
+ else
{
- /* Already made an entry for it */
Assert(numStrats == opcentry->numStrats);
Assert(numSupport == opcentry->numSupport);
- return opcentry;
}
- /* Need to fill in new entry */
- opcentry->valid = false; /* until known OK */
- opcentry->numStrats = numStrats;
- opcentry->numSupport = numSupport;
-
- if (numStrats > 0)
- opcentry->operatorOids = (Oid *)
- MemoryContextAllocZero(CacheMemoryContext,
- numStrats * sizeof(Oid));
- else
- opcentry->operatorOids = NULL;
+ /*
+ * When testing for cache-flush hazards, we intentionally disable the
+ * operator class cache and force reloading of the info on each call.
+ * This is helpful because we want to test the case where a cache flush
+ * occurs while we are loading the info, and it's very hard to provoke
+ * that if this happens only once per opclass per backend.
+ */
+#if defined(CLOBBER_CACHE_ALWAYS)
+ opcentry->valid = false;
+#endif
- if (numSupport > 0)
- opcentry->supportProcs = (RegProcedure *)
- MemoryContextAllocZero(CacheMemoryContext,
- numSupport * sizeof(RegProcedure));
- else
- opcentry->supportProcs = NULL;
+ if (opcentry->valid)
+ return opcentry;
/*
+ * Need to fill in new entry.
+ *
* To avoid infinite recursion during startup, force heap scans if we're
* looking up info for the opclasses used by the indexes we would like to
* reference here.
--
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