Lower *_freeze_max_age minimum values.

The old minimum values are rather large, making it time consuming to
test related behaviour. Additionally the current limits, especially for
multixacts, can be problematic in space-constrained systems. 10000000
multixacts can contain a lot of members.

Since there's no good reason for the current limits, lower them a good
bit. Setting them to 0 would be a bad idea, triggering endless vacuums,
so still retain a limit.

While at it fix autovacuum_multixact_freeze_max_age to refer to
multixact.c instead of varsup.c.

Reviewed-By: Robert Haas
Discussion: CA+TgmoYmQPHcrc3GSs7vwvrbTkbcGD9Gik=OztbDGGrovkkEzQ@mail.gmail.com
Backpatch: back to 9.0 (in parts)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index fcba3c59d03a93862f27aa4a7d12ab09d0e4b26c..17053aff68b7d05f7a361566708e2aba46444fc1 100644 (file)
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -2510,17 +2510,17 @@ static struct config_int ConfigureNamesInt[] =
        },
        &autovacuum_freeze_max_age,
        /* see pg_resetxlog if you change the upper-limit value */
-       200000000, 100000000, 2000000000,
+       200000000, 100000, 2000000000,
        NULL, NULL, NULL
    },
    {
-       /* see varsup.c for why this is PGC_POSTMASTER not PGC_SIGHUP */
+       /* see multixact.c for why this is PGC_POSTMASTER not PGC_SIGHUP */
        {"autovacuum_multixact_freeze_max_age", PGC_POSTMASTER, AUTOVACUUM,
            gettext_noop("Multixact age at which to autovacuum a table to prevent multixact wraparound."),
            NULL
        },
        &autovacuum_multixact_freeze_max_age,
-       400000000, 10000000, 2000000000,
+       400000000, 10000, 2000000000,
        NULL, NULL, NULL
    },
    {