Clean up some longstanding problems in shared-cache invalidation.

SI messages now include the relevant database OID, so that operations
in one database do not cause useless cache flushes in backends attached
to other databases.  Declare SI messages properly using a union, to
eliminate the former assumption that Oid is the same size as int or Index.
Rewrite the nearly-unreadable code in inval.c, and document it better.
Arrange for catcache flushes at end of command/transaction to happen before
relcache flushes do --- this avoids loading a new tuple into the catcache
while setting up new relcache entry, only to have it be flushed again
immediately.

1 files changed, 8 insertions, 15 deletions

diff --git a/src/include/storage/sinvaladt.h b/src/include/storage/sinvaladt.h
index 22b073350df..606304ce317 100644
--- a/src/include/storage/sinvaladt.h
+++ b/src/include/storage/sinvaladt.h
@@ -7,15 +7,15 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: sinvaladt.h,v 1.26 2001/03/22 04:01:09 momjian Exp $
+ * $Id: sinvaladt.h,v 1.27 2001/06/19 19:42:16 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #ifndef SINVALADT_H
 #define SINVALADT_H
 
-#include "storage/itemptr.h"
 #include "storage/shmem.h"
+#include "storage/sinval.h"
 
 /*
  * The shared cache invalidation manager is responsible for transmitting
@@ -45,6 +45,9 @@
  * large so that we don't need to do this often.  It must be a multiple of
  * MAXNUMMESSAGES so that the existing circular-buffer entries don't need
  * to be moved when we do it.
+ *
+ * The struct type SharedInvalidationMessage, defining the contents of
+ * a single message, is defined in sinval.h.
  */
 
 
@@ -61,15 +64,6 @@
 #define MAXNUMMESSAGES 4096
 #define MSGNUMWRAPAROUND (MAXNUMMESSAGES * 4096)
 
-/* The content of one shared-invalidation message */
-typedef struct SharedInvalidData
-{
-	int			cacheId;		/* XXX */
-	Index		hashIndex;
-	ItemPointerData pointerData;
-} SharedInvalidData;
-
-typedef SharedInvalidData *SharedInvalid;
 
 /* Per-backend state in shared invalidation structure */
 typedef struct ProcState
@@ -83,7 +77,6 @@ typedef struct ProcState
 /* Shared cache invalidation memory segment */
 typedef struct SISeg
 {
-
 	/*
 	 * General state information
 	 */
@@ -96,7 +89,7 @@ typedef struct SISeg
 	/*
 	 * Circular buffer holding shared-inval messages
 	 */
-	SharedInvalidData buffer[MAXNUMMESSAGES];
+	SharedInvalidationMessage buffer[MAXNUMMESSAGES];
 
 	/*
 	 * Per-backend state info.
@@ -117,9 +110,9 @@ extern SISeg *shmInvalBuffer;	/* pointer to the shared inval buffer */
 extern void SIBufferInit(int maxBackends);
 extern int	SIBackendInit(SISeg *segP);
 
-extern bool SIInsertDataEntry(SISeg *segP, SharedInvalidData *data);
+extern bool SIInsertDataEntry(SISeg *segP, SharedInvalidationMessage *data);
 extern int SIGetDataEntry(SISeg *segP, int backendId,
-			   SharedInvalidData *data);
+						  SharedInvalidationMessage *data);
 extern void SIDelExpiredDataEntries(SISeg *segP);
 
 #endif	 /* SINVALADT_H */