On Tue, Jul 4, 2017 at 9:23 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > > regression=# explain analyze select * from tenk1 where thousand < 10; > before: > Bitmap Heap Scan on tenk1 (cost=5.14..241.38 rows=110 width=244) (actual > time=0.121..0.623 rows=100 loops=1) > with patch: > Bitmap Heap Scan on tenk1 (cost=5.06..227.42 rows=100 width=244) (actual > time=0.054..0.300 rows=100 loops=1)
It's expected that the estimates will change with this patch. But I am wondering why should actual times vary so much. May be that's just accidental. Butthe actual timings are consistently lower with the patch except the last one > > regression=# explain analyze select * from tenk1 where thousand between 10 > and 10; > before: > Index Scan using tenk1_thous_tenthous on tenk1 (cost=0.29..8.30 rows=1 > width=244) (actual time=0.041..0.112 rows=10 loops=1) > with patch: > Bitmap Heap Scan on tenk1 (cost=4.39..39.52 rows=10 width=244) (actual > time=0.074..0.142 rows=10 loops=1) The actual time has increased even though estimation is correct. Those differences may just vanish if we take average of multiple runs and are not that important to ponder about. -- Best Wishes, Ashutosh Bapat EnterpriseDB Corporation The Postgres Database Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
