Postgres consistently does a sequential scan on the child partitions for this query select * from partitioned_table where partitioned_column > current_timestamp - interval 8 days where x in (select yy from z where colname like 'aaa%') If I replace the query with select * from partitioned_table where partitioned_column > current_timestamp - interval 8 days where x in (hardcode_value) The results are in line with expectation (very fast and uses a Bitmap Index Scan on the column X) -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance