Mark vacuum_defer_cleanup_age as PGC_POSTMASTER.

Following bug analysis of #7819 by Tom Lane

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 1e42a2619bf6c1bca9e04aee1e5d89b944332902..1f4114dd4bbe21555109ce8ab51e0eb7dcabf4f0 100644 (file)
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2059,8 +2059,7 @@ SET ENABLE_SEQSCAN TO OFF;
         is measured in terms of number of write transactions occurring on the
         primary server, it is difficult to predict just how much additional
         grace time will be made available to standby queries.
-        This parameter can only be set in the <filename>postgresql.conf</>
-        file or on the server command line.
+        This parameter can only be set at server start.
        </para>
        <para>
         You should also consider setting <varname>hot_standby_feedback</>

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a363441d8f7808496152b50831af0d5024e4e316..f9a5efe100c0d1de6deb87a5c399277042ed4c4f 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1853,7 +1853,12 @@ static struct config_int ConfigureNamesInt[] =
        },
 
        {
-               {"vacuum_defer_cleanup_age", PGC_SIGHUP, REPLICATION_MASTER,
+               /*
+                * Setting this to a higher value without restarting postmaster
+                * can cause various bugs in TOAST object removal, CLUSTER and
+                * possibly other places, so this must be changed only on restart.
+                */
+               {"vacuum_defer_cleanup_age", PGC_POSTMASTER, REPLICATION_MASTER,
                        gettext_noop("Number of transactions by which VACUUM and HOT cleanup should be deferred, if any."),
                        NULL
                },