postgres.git / summary / log / commit / refs

commit    69bd60672af63eaa8b19cdcea175df5ff172e80e
Author:   Amit Kapila <akapila@postgresql.org>
Date:     Wed Sep 16 02:15:44 2020 +0000
First released in: 14.0

    Fix initialization of RelationSyncEntry for streaming transactions.
    
    In commit 464824323e, for each RelationSyncEntry we maintained the list
    of xids (streamed_txns) for which we have already sent the schema. This
    helps us to track when to send the schema to the downstream node for
    replication of streaming transactions. Before this list got initialized,
    we were processing invalidation messages which access this list and led
    to an assertion failure.
    
    In passing, clean up the nearby code:
    
    * Initialize the list of xids with NIL instead of NULL which is our usual
    coding practice.
    * Remove the MemoryContext switch for creating a RelationSyncEntry in dynahash.
    
    Diagnosed-by: Amit Kapila and Tom Lane
    Author: Amit Kapila
    Reviewed-by: Tom Lane and Dilip Kumar
    Discussion: https://postgr.es/m/904373.1600033123@sss.pgh.pa.us


 src/backend/replication/pgoutput/pgoutput.c | 29 +++++++++++++++--------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 343f03129fe..eb1f23004e7 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -945,16 +945,26 @@ get_rel_sync_entry(PGOutputData *data, Oid relid)
 
 	Assert(RelationSyncCache != NULL);
 
-	/* Find cached function info, creating if not found */
-	oldctx = MemoryContextSwitchTo(CacheMemoryContext);
+	/* Find cached relation info, creating if not found */
 	entry = (RelationSyncEntry *) hash_search(RelationSyncCache,
 											  (void *) &relid,
 											  HASH_ENTER, &found);
-	MemoryContextSwitchTo(oldctx);
 	Assert(entry != NULL);
 
 	/* Not found means schema wasn't sent */
-	if (!found || !entry->replicate_valid)
+	if (!found)
+	{
+		/* immediately make a new entry valid enough to satisfy callbacks */
+		entry->schema_sent = false;
+		entry->streamed_txns = NIL;
+		entry->replicate_valid = false;
+		entry->pubactions.pubinsert = entry->pubactions.pubupdate =
+			entry->pubactions.pubdelete = entry->pubactions.pubtruncate = false;
+		entry->publish_as_relid = InvalidOid;
+	}
+
+	/* Validate the entry */
+	if (!entry->replicate_valid)
 	{
 		List	   *pubids = GetRelationPublications(relid);
 		ListCell   *lc;
@@ -977,9 +987,6 @@ get_rel_sync_entry(PGOutputData *data, Oid relid)
 		 * relcache considers all publications given relation is in, but here
 		 * we only need to consider ones that the subscriber requested.
 		 */
-		entry->pubactions.pubinsert = entry->pubactions.pubupdate =
-			entry->pubactions.pubdelete = entry->pubactions.pubtruncate = false;
-
 		foreach(lc, data->publications)
 		{
 			Publication *pub = lfirst(lc);
@@ -1054,12 +1061,6 @@ get_rel_sync_entry(PGOutputData *data, Oid relid)
 		entry->replicate_valid = true;
 	}
 
-	if (!found)
-	{
-		entry->schema_sent = false;
-		entry->streamed_txns = NULL;
-	}
-
 	return entry;
 }
 
@@ -1145,7 +1146,7 @@ rel_sync_cache_relation_cb(Datum arg, Oid relid)
 	{
 		entry->schema_sent = false;
 		list_free(entry->streamed_txns);
-		entry->streamed_txns = NULL;
+		entry->streamed_txns = NIL;
 	}
 }
 


[parent: 19c60ad69a91]