4 files changed, 19 insertions, 25 deletions
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 7c085b3f4f6..852ef775309 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -17,7 +17,6 @@
 #include "access/sdir.h"
 #include "nodes/bitmapset.h"
 #include "nodes/primnodes.h"
-#include "storage/itemptr.h"
 
 
 /* ----------------------------------------------------------------
@@ -793,13 +792,13 @@ typedef struct PlanRowMark
  * relations are recorded as a simple list of OIDs, and everything else
  * is represented as a list of PlanInvalItems.	A PlanInvalItem is designed
  * to be used with the syscache invalidation mechanism, so it identifies a
- * system catalog entry by cache ID and tuple TID.
+ * system catalog entry by cache ID and hash value.
  */
 typedef struct PlanInvalItem
 {
 	NodeTag		type;
 	int			cacheId;		/* a syscache ID, see utils/syscache.h */
-	ItemPointerData tupleId;	/* TID of the object's catalog tuple */
+	uint32		hashValue;		/* hash value of object's cache lookup key */
 } PlanInvalItem;
 
 #endif   /* PLANNODES_H */
diff --git a/src/include/storage/sinval.h b/src/include/storage/sinval.h
index aba474d2371..b468468fa48 100644
--- a/src/include/storage/sinval.h
+++ b/src/include/storage/sinval.h
@@ -14,7 +14,6 @@
 #ifndef SINVAL_H
 #define SINVAL_H
 
-#include "storage/itemptr.h"
 #include "storage/relfilenode.h"
 
 
@@ -32,22 +31,17 @@
  *
  * Catcache inval events are initially driven by detecting tuple inserts,
  * updates and deletions in system catalogs (see CacheInvalidateHeapTuple).
- * An update generates two inval events, one for the old tuple and one for
- * the new --- this is needed to get rid of both positive entries for the
- * old tuple, and negative cache entries associated with the new tuple's
- * cache key.  (This could perhaps be optimized down to one event when the
- * cache key is not changing, but for now we don't bother to try.)  Note that
- * the inval events themselves don't actually say whether the tuple is being
- * inserted or deleted.
+ * An update can generate two inval events, one for the old tuple and one for
+ * the new, but this is reduced to one event if the tuple's hash key doesn't
+ * change.  Note that the inval events themselves don't actually say whether
+ * the tuple is being inserted or deleted.  Also, since we transmit only a
+ * hash key, there is a small risk of unnecessary invalidations due to chance
+ * matches of hash keys.
  *
  * Note that some system catalogs have multiple caches on them (with different
  * indexes).  On detecting a tuple invalidation in such a catalog, separate
- * catcache inval messages must be generated for each of its caches.  The
- * catcache inval messages carry the hash value for the target tuple, so
- * that the catcache only needs to search one hash chain not all its chains,
- * and so that negative cache entries can be recognized with good accuracy.
- * (Of course this assumes that all the backends are using identical hashing
- * code, but that should be OK.)
+ * catcache inval messages must be generated for each of its caches, since
+ * the hash keys will generally be different.
  *
  * Catcache and relcache invalidations are transactional, and so are sent
  * to other backends upon commit.  Internally to the generating backend,
@@ -62,9 +56,7 @@
 
 typedef struct
 {
-	/* note: field layout chosen with an eye to alignment concerns */
 	int8		id;				/* cache ID --- must be first */
-	ItemPointerData tuplePtr;	/* tuple identifier in cached relation */
 	Oid			dbId;			/* database ID, or 0 if a shared relation */
 	uint32		hashValue;		/* hash value of key for this catcache */
 } SharedInvalCatcacheMsg;
@@ -91,6 +83,7 @@ typedef struct
 
 typedef struct
 {
+	/* note: field layout chosen to pack into 16 bytes */
 	int8		id;				/* type field --- must be first */
 	int8		backend_hi;		/* high bits of backend ID, if temprel */
 	uint16		backend_lo;		/* low bits of backend ID, if temprel */
diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h
index 7a990528e75..84163d0b7fb 100644
--- a/src/include/utils/catcache.h
+++ b/src/include/utils/catcache.h
@@ -181,11 +181,11 @@ extern void ReleaseCatCacheList(CatCList *list);
 
 extern void ResetCatalogCaches(void);
 extern void CatalogCacheFlushCatalog(Oid catId);
-extern void CatalogCacheIdInvalidate(int cacheId, uint32 hashValue,
-						 ItemPointer pointer);
+extern void CatalogCacheIdInvalidate(int cacheId, uint32 hashValue);
 extern void PrepareToInvalidateCacheTuple(Relation relation,
 							  HeapTuple tuple,
-						   void (*function) (int, uint32, ItemPointer, Oid));
+							  HeapTuple newtuple,
+							  void (*function) (int, uint32, Oid));
 
 extern void PrintCatCacheLeakWarning(HeapTuple tuple);
 extern void PrintCatCacheListLeakWarning(CatCList *list);
diff --git a/src/include/utils/inval.h b/src/include/utils/inval.h
index dda2a63d6e1..606b778f10e 100644
--- a/src/include/utils/inval.h
+++ b/src/include/utils/inval.h
@@ -19,7 +19,7 @@
 #include "utils/relcache.h"
 
 
-typedef void (*SyscacheCallbackFunction) (Datum arg, int cacheid, ItemPointer tuplePtr);
+typedef void (*SyscacheCallbackFunction) (Datum arg, int cacheid, uint32 hashvalue);
 typedef void (*RelcacheCallbackFunction) (Datum arg, Oid relid);
 
 
@@ -39,7 +39,9 @@ extern void PostPrepare_Inval(void);
 
 extern void CommandEndInvalidationMessages(void);
 
-extern void CacheInvalidateHeapTuple(Relation relation, HeapTuple tuple);
+extern void CacheInvalidateHeapTuple(Relation relation,
+						 HeapTuple tuple,
+						 HeapTuple newtuple);
 
 extern void CacheInvalidateCatalog(Oid catalogId);
 
@@ -60,7 +62,7 @@ extern void CacheRegisterSyscacheCallback(int cacheid,
 extern void CacheRegisterRelcacheCallback(RelcacheCallbackFunction func,
 							  Datum arg);
 
-extern void CallSyscacheCallbacks(int cacheid, ItemPointer tuplePtr);
+extern void CallSyscacheCallbacks(int cacheid, uint32 hashvalue);
 
 extern void inval_twophase_postcommit(TransactionId xid, uint16 info,
 						  void *recdata, uint32 len);