From d2505681211b4803cae916e9f4c2331943f851dc Mon Sep 17 00:00:00 2001 From: Amit Kapila Date: Tue, 1 Jun 2021 14:25:19 +0530 Subject: [PATCH] pgoutput: Fix memory leak due to RelationSyncEntry.map. Release memory allocated when creating the tuple-conversion map and its component TupleDescs when its owning sync entry is invalidated. TupleDescs must also be freed when no map is deemed necessary, to begin with. Reported-by: Andres Freund Author: Amit Langote Reviewed-by: Takamichi Osumi, Amit Kapila Backpatch-through: 13, where it was introduced Discussion: https://postgr.es/m/MEYP282MB166933B1AB02B4FE56E82453B64D9@MEYP282MB1669.AUSP282.PROD.OUTLOOK.COM --- src/backend/replication/pgoutput/pgoutput.c | 49 ++++++++++++++++++--- src/test/subscription/t/013_partition.pl | 28 +++++++++++- 2 files changed, 69 insertions(+), 8 deletions(-) diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c index c5fbebf55a..d9e45bab4a 100644 --- a/src/backend/replication/pgoutput/pgoutput.c +++ b/src/backend/replication/pgoutput/pgoutput.c @@ -57,6 +57,10 @@ static void send_relation_and_attrs(Relation relation, LogicalDecodingContext *c /* * Entry in the map used to remember which relation schemas we sent. * + * The schema_sent flag determines if the current schema record for the + * relation (and for its ancestor if publish_as_relid is set) was already sent + * to the subscriber (in which case we don't need to send it again). + * * For partitions, 'pubactions' considers not only the table's own * publications, but also those of all of its ancestors. */ @@ -64,10 +68,6 @@ typedef struct RelationSyncEntry { Oid relid; /* relation oid */ - /* - * Did we send the schema? If ancestor relid is set, its schema must also - * have been sent for this to be true. - */ bool schema_sent; bool replicate_valid; @@ -292,10 +292,17 @@ static void maybe_send_schema(LogicalDecodingContext *ctx, Relation relation, RelationSyncEntry *relentry) { + /* Nothing to do if we already sent the schema. */ if (relentry->schema_sent) return; - /* If needed, send the ancestor's schema first. */ + /* + * Nope, so send the schema. If the changes will be published using an + * ancestor's schema, not the relation's own, send that ancestor's schema + * before sending relation's own (XXX - maybe sending only the former + * suffices?). This is also a good place to set the map that will be used + * to convert the relation's tuples into the ancestor's format, if needed. + */ if (relentry->publish_as_relid != RelationGetRelid(relation)) { Relation ancestor = RelationIdGetRelation(relentry->publish_as_relid); @@ -305,8 +312,21 @@ maybe_send_schema(LogicalDecodingContext *ctx, /* Map must live as long as the session does. */ oldctx = MemoryContextSwitchTo(CacheMemoryContext); - relentry->map = convert_tuples_by_name(CreateTupleDescCopy(indesc), - CreateTupleDescCopy(outdesc)); + + /* + * Make copies of the TupleDescs that will live as long as the map + * does before putting into the map. + */ + indesc = CreateTupleDescCopy(indesc); + outdesc = CreateTupleDescCopy(outdesc); + relentry->map = convert_tuples_by_name(indesc, outdesc); + if (relentry->map == NULL) + { + /* Map not necessary, so free the TupleDescs too. */ + FreeTupleDesc(indesc); + FreeTupleDesc(outdesc); + } + MemoryContextSwitchTo(oldctx); send_relation_and_attrs(ancestor, ctx); RelationClose(ancestor); @@ -759,6 +779,7 @@ get_rel_sync_entry(PGOutputData *data, Oid relid) list_free(pubids); entry->publish_as_relid = publish_as_relid; + entry->map = NULL; /* will be set by maybe_send_schema() if needed */ entry->replicate_valid = true; } @@ -801,9 +822,23 @@ rel_sync_cache_relation_cb(Datum arg, Oid relid) /* * Reset schema sent status as the relation definition may have changed. + * Also, free any objects that depended on the earlier definition. */ if (entry != NULL) + { entry->schema_sent = false; + if (entry->map) + { + /* + * Must free the TupleDescs contained in the map explicitly, + * because free_conversion_map() doesn't. + */ + FreeTupleDesc(entry->map->indesc); + FreeTupleDesc(entry->map->outdesc); + free_conversion_map(entry->map); + } + entry->map = NULL; + } } /* diff --git a/src/test/subscription/t/013_partition.pl b/src/test/subscription/t/013_partition.pl index 4b7d637c70..046e18c700 100644 --- a/src/test/subscription/t/013_partition.pl +++ b/src/test/subscription/t/013_partition.pl @@ -3,7 +3,7 @@ use strict; use warnings; use PostgresNode; use TestLib; -use Test::More tests => 54; +use Test::More tests => 56; # setup @@ -621,3 +621,29 @@ is($result, qq(), 'truncate of tab3 replicated'); $result = $node_subscriber2->safe_psql('postgres', "SELECT a FROM tab3_1"); is($result, qq(), 'truncate of tab3_1 replicated'); + +# check that the map to convert tuples from leaf partition to the root +# table is correctly rebuilt when a new column is added +$node_publisher->safe_psql('postgres', + "ALTER TABLE tab2 DROP b, ADD COLUMN c text DEFAULT 'pub_tab2', ADD b text"); +$node_publisher->safe_psql('postgres', + "INSERT INTO tab2 (a, b) VALUES (1, 'xxx'), (3, 'yyy'), (5, 'zzz')"); +$node_publisher->safe_psql('postgres', + "INSERT INTO tab2 (a, b, c) VALUES (6, 'aaa', 'xxx_c')"); + +$node_publisher->wait_for_catchup('sub_viaroot'); +$node_publisher->wait_for_catchup('sub2'); + +$result = $node_subscriber1->safe_psql('postgres', + "SELECT c, a, b FROM tab2 ORDER BY 1, 2"); +is( $result, qq(pub_tab2|1|xxx +pub_tab2|3|yyy +pub_tab2|5|zzz +xxx_c|6|aaa), 'inserts into tab2 replicated'); + +$result = $node_subscriber2->safe_psql('postgres', + "SELECT c, a, b FROM tab2 ORDER BY 1, 2"); +is( $result, qq(pub_tab2|1|xxx +pub_tab2|3|yyy +pub_tab2|5|zzz +xxx_c|6|aaa), 'inserts into tab2 replicated');