On Apr 25, 2007, at 7:36 AM, Listmail wrote:
Is there a way to know how many pages were hit by a Bitmap Heap
scan ?
For instance :
Bitmap Heap Scan on posts
(cost=56.71..295.24 rows=2123 width=67)
(actual time=0.575..1.462 rows=2160 loops=1)
I'd like to know if it hit 2160 pages (ie I should really run
CLUSTER) or 50 pages (ie. my table is well clustered, everything
cool).
Since, when it's cached, it's so fast anyway I cant' tell the
difference, but when it's not cached, it is important.
This would give an interesting probe for EXPLAIN ANALYZE tuning...
If you don't have anything else running in the database and you've
got stats_block_level on, you could probably determine how many pages
are being run by consulting the appropriate pg_statio_* view.
--
Jim Nasby jim@xxxxxxxxx
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
