postgres.git / summary / log / commit / refs

commit    95558bc8ff89c5887f1bffc9d152ca603637e2c0
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Thu Feb 23 20:40:28 2023 +0000
First released in: 16.0, 11.20, 12.15, 13.11, 14.8, 15.3

    Don't repeatedly register cache callbacks in pgoutput plugin.
    
    Multiple cycles of starting up and shutting down the plugin within a
    single session would eventually lead to "out of relcache_callback_list
    slots", because pgoutput_startup blindly re-registered its cache
    callbacks each time.  Fix it to register them only once, as all other
    users of cache callbacks already take care to do.
    
    This has been broken all along, so back-patch to all supported branches.
    
    Shi Yu
    
    Discussion: https://postgr.es/m/OSZPR01MB631004A78D743D68921FFAD3FDA79@OSZPR01MB6310.jpnprd01.prod.outlook.com


 src/backend/replication/pgoutput/pgoutput.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 6710f983ea4..1b7a16d889b 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -152,6 +152,7 @@ pgoutput_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
 				 bool is_init)
 {
 	PGOutputData *data = palloc0(sizeof(PGOutputData));
+	static bool publication_callback_registered = false;
 
 	/* Create our memory context for private allocations. */
 	data->context = AllocSetContextCreate(ctx->context,
@@ -196,9 +197,18 @@ pgoutput_startup(LogicalDecodingContext *ctx, OutputPluginOptions *opt,
 		/* Init publication state. */
 		data->publications = NIL;
 		publications_valid = false;
-		CacheRegisterSyscacheCallback(PUBLICATIONOID,
-									  publication_invalidation_cb,
-									  (Datum) 0);
+
+		/*
+		 * Register callback for pg_publication if we didn't already do that
+		 * during some previous call in this process.
+		 */
+		if (!publication_callback_registered)
+		{
+			CacheRegisterSyscacheCallback(PUBLICATIONOID,
+										  publication_invalidation_cb,
+										  (Datum) 0);
+			publication_callback_registered = true;
+		}
 
 		/* Initialize relation schema cache. */
 		init_rel_sync_cache(CacheMemoryContext);
@@ -503,8 +513,10 @@ static void
 init_rel_sync_cache(MemoryContext cachectx)
 {
 	HASHCTL		ctl;
+	static bool relation_callbacks_registered = false;
 	MemoryContext old_ctxt;
 
+	/* Nothing to do if hash table already exists */
 	if (RelationSyncCache != NULL)
 		return;
 
@@ -522,10 +534,16 @@ init_rel_sync_cache(MemoryContext cachectx)
 
 	Assert(RelationSyncCache != NULL);
 
+	/* No more to do if we already registered callbacks */
+	if (relation_callbacks_registered)
+		return;
+
 	CacheRegisterRelcacheCallback(rel_sync_cache_relation_cb, (Datum) 0);
 	CacheRegisterSyscacheCallback(PUBLICATIONRELMAP,
 								  rel_sync_cache_publication_cb,
 								  (Datum) 0);
+
+	relation_callbacks_registered = true;
 }
 
 /*


[parent: 98b83b734982]