Fix data inconsistency between publisher and subscriber.

We were not updating the partition map cache in the subscriber even when
the corresponding remote rel is changed. Due to this data was getting
incorrectly replicated for partition tables after the publisher has
changed the table schema.

Fix it by resetting the required entries in the partition map cache after
receiving a new relation mapping from the publisher.

Reported-by: Shi Yu
Author: Shi Yu, Hou Zhijie
Reviewed-by: Amit Langote, Amit Kapila
Backpatch-through: 13, where it was introduced
Discussion: https://postgr.es/m/OSZPR01MB6310F46CD425A967E4AEF736FDA49@OSZPR01MB6310.jpnprd01.prod.outlook.com

2 files changed, 37 insertions, 0 deletions

diff --git a/src/backend/replication/logical/relation.c b/src/backend/replication/logical/relation.c
index 5f4689f1822..5c7e9d11ac8 100644
--- a/src/backend/replication/logical/relation.c
+++ b/src/backend/replication/logical/relation.c
@@ -487,6 +487,40 @@ logicalrep_partmap_invalidate_cb(Datum arg, Oid reloid)
 }
 
 /*
+ * Reset the entries in the partition map that refer to remoterel.
+ *
+ * Called when new relation mapping is sent by the publisher to update our
+ * expected view of incoming data from said publisher.
+ *
+ * Note that we don't update the remoterel information in the entry here,
+ * we will update the information in logicalrep_partition_open to avoid
+ * unnecessary work.
+ */
+void
+logicalrep_partmap_reset_relmap(LogicalRepRelation *remoterel)
+{
+	HASH_SEQ_STATUS status;
+	LogicalRepPartMapEntry *part_entry;
+	LogicalRepRelMapEntry *entry;
+
+	if (LogicalRepPartMap == NULL)
+		return;
+
+	hash_seq_init(&status, LogicalRepPartMap);
+	while ((part_entry = (LogicalRepPartMapEntry *) hash_seq_search(&status)) != NULL)
+	{
+		entry = &part_entry->relmapentry;
+
+		if (entry->remoterel.remoteid != remoterel->remoteid)
+			continue;
+
+		logicalrep_relmap_free_entry(entry);
+
+		memset(entry, 0, sizeof(LogicalRepRelMapEntry));
+	}
+}
+
+/*
  * Initialize the partition map cache.
  */
 static void
diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c
index 833b2809d0b..bf97fa44ba2 100644
--- a/src/backend/replication/logical/worker.c
+++ b/src/backend/replication/logical/worker.c
@@ -1191,6 +1191,9 @@ apply_handle_relation(StringInfo s)
 
 	rel = logicalrep_read_rel(s);
 	logicalrep_relmap_update(rel);
+
+	/* Also reset all entries in the partition map that refer to remoterel. */
+	logicalrep_partmap_reset_relmap(rel);
 }
 
 /*