From da8bd5d424e00a3dd38bfc4f440c0ac346c5b3c1 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Mon, 30 Dec 2024 13:34:01 +0900 Subject: [PATCH] Fix memory leak in pgoutput with relation attribute map pgoutput caches the attribute map of a relation, that is free()'d only when validating a RelationSyncEntry. However, this code path is not taken when calling any of the SQL functions able to do some logical decoding, like pg_logical_slot_{get,peek}_changes(), leaking some memory into CacheMemoryContext on repeated calls. To address this, a relation's attribute map is allocated in PGOutputData's cachectx, free()'d at the end of the execution of these SQL functions when logical decoding ends. This is available down to 15. v13 and v14 have a similar leak, which will be dealt with later. Reported-by: Masahiko Sawada Author: Vignesh C Reviewed-by: Hou Zhijie Discussion: https://postgr.es/m/CAD21AoDkAhQVSukOfH3_reuF-j4EU0-HxMqU3dU+bSTxsqT14Q@mail.gmail.com Discussion: https://postgr.es/m/CALDaNm1hewNAsZ_e6FF52a=9drmkRJxtEPrzCB6-9mkJyeBBqA@mail.gmail.com Backpatch-through: 15 --- src/backend/replication/pgoutput/pgoutput.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c index e178bd77abc..64f62de635f 100644 --- a/src/backend/replication/pgoutput/pgoutput.c +++ b/src/backend/replication/pgoutput/pgoutput.c @@ -1139,8 +1139,8 @@ init_tuple_slot(PGOutputData *data, Relation relation, TupleDesc indesc = RelationGetDescr(relation); TupleDesc outdesc = RelationGetDescr(ancestor); - /* Map must live as long as the session does. */ - oldctx = MemoryContextSwitchTo(CacheMemoryContext); + /* Map must live as long as the logical decoding context. */ + oldctx = MemoryContextSwitchTo(data->cachectx); entry->attrmap = build_attrmap_by_name_if_req(indesc, outdesc); -- 2.30.2