Fix filtering of unsupported relations in logical replication

petere · petere · commit bc1adc651b8e · 2018-02-23T22:13:21.000-05:00
In the pgoutput plugin, skip changes for relations that are not
publishable, per is_publishable_class().  This concerns in particular
materialized views and information_schema tables.  While those relations
cannot be part of a publication, per existing checks, they will be
considered by a FOR ALL TABLES publication.  A subscription would not
actually apply changes for those relations, again per existing checks,
but trying to match incoming changes to local tables on the subscriber
would lead to errors if no matching local table exists.  Skipping those
changes on the publisher avoids sending useless changes and eliminates
the error.

Bug: #15044
Reported-by: Chad Trabant &lt;chad@iris.washington.edu&gt;
Reviewed-by: Petr Jelinek &lt;petr.jelinek@2ndquadrant.com&gt;
diff --git a/src/backend/catalog/pg_publication.c b/src/backend/catalog/pg_publication.c
@@ -105,6 +105,15 @@ is_publishable_class(Oid relid, Form_pg_class reltuple)
 		relid >= FirstNormalObjectId;
 }
 
+/*
+ * Another variant of this, taking a Relation.
+ */
+bool
+is_publishable_relation(Relation rel)
+{
+	return is_publishable_class(RelationGetRelid(rel), rel->rd_rel);
+}
+
 
 /*
  * SQL-callable variant of the above
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
@@ -262,6 +262,9 @@ pgoutput_change(LogicalDecodingContext *ctx, ReorderBufferTXN *txn,
 	MemoryContext old;
 	RelationSyncEntry *relentry;
 
+	if (!is_publishable_relation(relation))
+		return;
+
 	relentry = get_rel_sync_entry(data, RelationGetRelid(relation));
 
 	/* First check the table filter */
diff --git a/src/include/catalog/pg_publication.h b/src/include/catalog/pg_publication.h
@@ -93,6 +93,7 @@ extern List *GetPublicationRelations(Oid pubid);
 extern List *GetAllTablesPublications(void);
 extern List *GetAllTablesPublicationRelations(void);
 
+extern bool is_publishable_relation(Relation rel);
 extern ObjectAddress publication_add_relation(Oid pubid, Relation targetrel,
 						 bool if_not_exists);
 
diff --git a/src/test/subscription/t/009_matviews.pl b/src/test/subscription/t/009_matviews.pl
@@ -0,0 +1,45 @@
+# Test materialized views behavior
+use strict;
+use warnings;
+use PostgresNode;
+use TestLib;
+use Test::More tests => 1;
+
+my $node_publisher = get_new_node('publisher');
+$node_publisher->init(allows_streaming => 'logical');
+$node_publisher->start;
+
+my $node_subscriber = get_new_node('subscriber');
+$node_subscriber->init(allows_streaming => 'logical');
+$node_subscriber->start;
+
+my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
+my $appname           = 'replication_test';
+
+$node_publisher->safe_psql('postgres',
+	"CREATE PUBLICATION mypub FOR ALL TABLES;");
+$node_subscriber->safe_psql('postgres',
+"CREATE SUBSCRIPTION mysub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION mypub;"
+);
+
+$node_publisher->safe_psql('postgres', q{CREATE TABLE test1 (a int PRIMARY KEY, b text)});
+$node_publisher->safe_psql('postgres', q{INSERT INTO test1 (a, b) VALUES (1, 'one'), (2, 'two');});
+
+$node_subscriber->safe_psql('postgres', q{CREATE TABLE test1 (a int PRIMARY KEY, b text);});
+
+$node_publisher->wait_for_catchup($appname);
+
+# Materialized views are not supported by logical replication, but
+# logical decoding does produce change information for them, so we
+# need to make sure they are properly ignored. (bug #15044)
+
+# create a MV with some data
+$node_publisher->safe_psql('postgres', q{CREATE MATERIALIZED VIEW testmv1 AS SELECT * FROM test1;});
+$node_publisher->wait_for_catchup($appname);
+# There is no equivalent relation on the subscriber, but MV data is
+# not replicated, so this does not hang.
+
+pass "materialized view data not replicated";
+
+$node_subscriber->stop;
+$node_publisher->stop;
