Make min_parallel_relation_size's default value platform-independent.

tglsfdc · tglsfdc · commit 5472ed3e9bc2 · 2016-09-15T11:23:25.000-04:00
The documentation states that the default value is 8MB, but this was only true at BLCKSZ = 8kB, because the default was hard-coded as 1024. Make the code match the docs by computing the default as 8MB/BLCKSZ. Oversight in commit 75be664, noted pursuant to a gripe from Peter E. Discussion: <90634e20-097a-e4fd-67d5-fb2c42f0dd71@2ndquadrant.com>
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
@@ -2758,7 +2758,7 @@ static struct config_int ConfigureNamesInt[] =
 			GUC_UNIT_BLOCKS,
 		},
 		&min_parallel_relation_size,
-		1024, 0, INT_MAX / 3,
+		(8 * 1024 * 1024) / BLCKSZ, 0, INT_MAX / 3,
 		NULL, NULL, NULL
 	},
 
