Make min_parallel_relation_size's default value platform-independent.

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 75be66464, 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
index 7b7352b5cb2ec009f2b89bdd4222a70261c8de02..bc9d33f6ff1bb04e847a961f9fb342117b441448 100644 (file)
--- 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
        },