From cb9079cd51a2df677dc182aec72d88383b9c2a79 Mon Sep 17 00:00:00 2001 From: Peter Eisentraut <peter_e@gmx.net> Date: Mon, 3 Jul 2017 22:47:06 -0400 Subject: [PATCH] Improve subscription locking This avoids "tuple concurrently updated" errors when a ALTER or DROP SUBSCRIPTION writes to pg_subscription_rel at the same time as a worker. Author: Petr Jelinek <petr.jelinek@2ndquadrant.com> --- src/backend/catalog/pg_subscription.c | 4 ++++ src/backend/commands/subscriptioncmds.c | 3 +++ 2 files changed, 7 insertions(+) diff --git a/src/backend/catalog/pg_subscription.c b/src/backend/catalog/pg_subscription.c index c69c461b62a..fb53d71cd66 100644 --- a/src/backend/catalog/pg_subscription.c +++ b/src/backend/catalog/pg_subscription.c @@ -28,6 +28,8 @@ #include "nodes/makefuncs.h" +#include "storage/lmgr.h" + #include "utils/array.h" #include "utils/builtins.h" #include "utils/fmgroids.h" @@ -246,6 +248,8 @@ SetSubscriptionRelState(Oid subid, Oid relid, char state, bool nulls[Natts_pg_subscription_rel]; Datum values[Natts_pg_subscription_rel]; + LockSharedObject(SubscriptionRelationId, subid, 0, AccessShareLock); + rel = heap_open(SubscriptionRelRelationId, RowExclusiveLock); /* Try finding existing mapping. */ diff --git a/src/backend/commands/subscriptioncmds.c b/src/backend/commands/subscriptioncmds.c index 9cbd36f6463..6dc3f6ee000 100644 --- a/src/backend/commands/subscriptioncmds.c +++ b/src/backend/commands/subscriptioncmds.c @@ -644,6 +644,9 @@ AlterSubscription(AlterSubscriptionStmt *stmt) subid = HeapTupleGetOid(tup); sub = GetSubscription(subid, false); + /* Lock the subscription so nobody else can do anything with it. */ + LockSharedObject(SubscriptionRelationId, subid, 0, AccessExclusiveLock); + /* Form a new tuple. */ memset(values, 0, sizeof(values)); memset(nulls, false, sizeof(nulls));