From 0bcadf81495789fabb19b805a3ca2bb0df77dcc6 Mon Sep 17 00:00:00 2001
From: Marko Kreen <markokr@gmail.com>
Date: Mon, 27 Feb 2012 02:09:22 +0200
Subject: [PATCH] Sync with cache invalidation changes in 9.2

---
 src/cluster.c  | 21 ++++++++++-----------
 src/plproxy.h  |  5 +++--
 src/rowstamp.h | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 13 deletions(-)

diff --git a/src/cluster.c b/src/cluster.c
index de803ad..e823def 100644
--- a/src/cluster.c
+++ b/src/cluster.c
@@ -531,7 +531,7 @@ reload_sqlmed_cluster(ProxyFunction *func, ProxyCluster *cluster,
     if (!HeapTupleIsValid(tup))
         elog(ERROR, "cache lookup failed for foreign server %u", foreign_server->serverid);
 
-	cluster->clusterTupleId = tup->t_self;
+	scstamp_set(FOREIGNSERVEROID, &cluster->clusterStamp, tup);
 	ReleaseSysCache(tup);
 
     tup = SearchSysCache(USERMAPPINGUSERSERVER,
@@ -551,7 +551,8 @@ reload_sqlmed_cluster(ProxyFunction *func, ProxyCluster *cluster,
 				user_mapping->userid, foreign_server->serverid);
 	}
 
-	cluster->umTupleId = tup->t_self;
+	scstamp_set(USERMAPPINGOID, &cluster->umStamp, tup);
+
 	ReleaseSysCache(tup);
 
 	/*
@@ -684,7 +685,7 @@ determine_compat_mode(ProxyCluster *cluster)
  * functions.
  */
 static void
-ClusterSyscacheCallback(Datum arg, int cacheid, ItemPointer tuplePtr)
+ClusterSyscacheCallback(Datum arg, int cacheid, SCInvalArg newStamp)
 {
 	ProxyCluster *cluster;
 
@@ -695,25 +696,23 @@ ClusterSyscacheCallback(Datum arg, int cacheid, ItemPointer tuplePtr)
 			/* already invalidated */
 			continue;
 		}
-		else if (!tuplePtr)
-		{
-			/* invalidate all */
-			cluster->needs_reload = true;
-		}
 		else if (!cluster->sqlmed_cluster)
 		{
 			/* allow new SQL/MED servers to override compat definitions */
-			cluster->needs_reload = (cacheid == FOREIGNSERVEROID);
+			if (cacheid == FOREIGNSERVEROID)
+				cluster->needs_reload = true;
 		}
 		else if (cacheid == USERMAPPINGOID)
 		{
 			/* user mappings changed */
-			cluster->needs_reload = ItemPointerEquals(tuplePtr, &cluster->umTupleId);
+			if (scstamp_check(cacheid, &cluster->umStamp, newStamp))
+				cluster->needs_reload = true;
 		}
 		else if (cacheid == FOREIGNSERVEROID)
 		{
 			/* server definitions changed */
-			cluster->needs_reload = ItemPointerEquals(tuplePtr, &cluster->clusterTupleId);
+			if (scstamp_check(cacheid, &cluster->clusterStamp, newStamp))
+				cluster->needs_reload = true;
 		}
 	}
 }
diff --git a/src/plproxy.h b/src/plproxy.h
index 72b5ae4..c82fb11 100644
--- a/src/plproxy.h
+++ b/src/plproxy.h
@@ -54,6 +54,7 @@
 #include <utils/lsyscache.h>
 #include <utils/memutils.h>
 #include <utils/syscache.h>
+
 #include "rowstamp.h"
 
 #include <libpq-fe.h>
@@ -196,8 +197,8 @@ typedef struct ProxyCluster
 	 * SQL/MED clusters: TIDs of the foreign server and user mapping catalog tuples.
 	 * Used in to perform cluster invalidation in syscache callbacks.
 	 */
-	ItemPointerData		clusterTupleId;
-	ItemPointerData		umTupleId;
+	SysCacheStamp clusterStamp;
+	SysCacheStamp umStamp;
 
 	/* notice processing: provide info about currently executing function */
 	struct ProxyFunction	*cur_func;
diff --git a/src/rowstamp.h b/src/rowstamp.h
index acd51b2..37ca378 100644
--- a/src/rowstamp.h
+++ b/src/rowstamp.h
@@ -48,3 +48,52 @@ static inline bool plproxy_check_stamp(RowStamp *stamp, HeapTuple tup)
 
 #endif
 
+/*
+ * SyscacheCallback check changed in 9.2.
+ */
+
+#if PG_VERSION_NUM >= 90200
+
+typedef uint32 SCInvalArg;
+typedef struct SysCacheStamp {
+	uint32 cacheid;
+	uint32 hashValue;
+} SysCacheStamp;
+
+static inline void scstamp_set(int cache, SysCacheStamp *stamp, HeapTuple tup)
+{
+	Oid oid = HeapTupleGetOid(tup);
+	stamp->cacheid = cache;
+	stamp->hashValue = GetSysCacheHashValue1(cache, oid);
+}
+
+static inline bool scstamp_check(int cache, SysCacheStamp *stamp, uint32 hashValue)
+{
+	if (cache != stamp->cacheid)
+		elog(WARNING, "cache id mismatch: stamp:%d cur:%d", stamp->cacheid, cache);
+	return !hashValue || stamp->hashValue == hashValue;
+}
+
+#else
+
+/*
+ * Pre-9.2 cache invalidation.
+ */
+
+typedef ItemPointer SCInvalArg;
+typedef struct SysCacheStamp {
+	ItemPointerData     tupleId;
+} SysCacheStamp;
+
+static inline void scstamp_set(int cache, SysCacheStamp *stamp, HeapTuple tup)
+{
+	stamp->tupleId = tup->t_self;
+}
+
+static inline bool scstamp_check(int cache, SysCacheStamp *stamp, ItemPointer scrow)
+{
+	return !scrow || ItemPointerEquals(&stamp->tupleId, scrow);
+}
+
+#endif
+
-- 
2.39.5