On Thu, Jun 20, 2019 at 12:09:13PM -0600, Michael Lewis wrote: > For kicks I tried the example given and got the below which seems more > expected. Do you just mean that it ran faster the 2nd time ? Isn't that just due just to cache effects ? Rerun them both back to back. See that the "actual" rowcount of the Index Scan is higher with tigher condition: > -> Bitmap Index Scan on idx_brin_test_brin (cost=0.00..3.32 rows=14286 width=0) (actual time=0.018..0.019 rows=640 loops=1) > Index Cond: (id >= 90000) > -> Bitmap Index Scan on idx_brin_test_brin (cost=0.00..3.31 rows=7143 width=0) (actual time=0.026..0.027 rows=1280 loops=1) > Index Cond: ((id >= 90000) AND (r = ANY ('{1,3}'::integer[])))