Lower *_freeze_max_age minimum values.

anarazel · anarazel · commit 078d471a909a · 2015-09-24T14:53:33.000+02:00
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: 9.0 (in parts)
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
@@ -1973,7 +1973,7 @@ static struct config_int ConfigureNamesInt[] =
 		},
 		&autovacuum_freeze_max_age,
 		/* see pg_resetxlog if you change the upper-limit value */
-		200000000, 100000000, 2000000000, NULL, NULL
+		200000000, 100000, 2000000000, NULL, NULL
 	},
 	{
 		/* see max_connections */

Original file line number	Diff line number	Diff line change
`@@ -1973,7 +1973,7 @@ static struct config_int ConfigureNamesInt[] =`
`1973`	`1973`	`},`
`1974`	`1974`	`&autovacuum_freeze_max_age,`
`1975`	`1975`	`/* see pg_resetxlog if you change the upper-limit value */`
`1976`		`- 200000000, 100000000, 2000000000, NULL, NULL`
	`1976`	`+ 200000000, 100000, 2000000000, NULL, NULL`
`1977`	`1977`	`},`
`1978`	`1978`	`{`
`1979`	`1979`	`/* see max_connections */`