The following bug has been logged online: Bug reference: 5733 Logged by: Marcus Wirsing Email address: m...@hesotech.de PostgreSQL version: 9.0.1 Operating system: Windows XP 32 Description: Strange planer behaviour with inherited tables Details:
when I execute the following script, the planer always makes a seq. scan over all child tables. drop schema if exists schema_0 cascade; drop schema if exists schema_1 cascade; drop schema if exists schema_2 cascade; create schema schema_0; create schema schema_1; create schema schema_2; CREATE TABLE schema_0.testtab ( entry bigserial NOT NULL, status integer, chnsetid integer, dt_package timestamp with time zone, dwell interval, cnt_mv integer, min_mv real[], PRIMARY KEY (entry) ); create table schema_1.testtab (primary key(entry)) inherits (schema_0.testtab); create table schema_2.testtab (primary key(entry)) inherits (schema_0.testtab); EXPLAIN SELECT entry FROM schema_0.testtab where entry > 1000 order by entry limit 1; result: "Limit (cost=62.73..62.73 rows=1 width=8)" " -> Sort (cost=62.73..64.66 rows=771 width=8)" " Sort Key: schema_0.testtab.entry" " -> Result (cost=0.00..58.88 rows=771 width=8)" " -> Append (cost=0.00..58.88 rows=771 width=8)" " -> Seq Scan on testtab (cost=0.00..19.63 rows=257 width=8)" " Filter: (entry > 1000)" " -> Seq Scan on testtab (cost=0.00..19.63 rows=257 width=8)" " Filter: (entry > 1000)" " -> Seq Scan on testtab (cost=0.00..19.63 rows=257 width=8)" " Filter: (entry > 1000)" when I remove the min_mv real[] the planer makes an index scan as expected. " -> Sort (cost=70.55..73.30 rows=1101 width=8)" " Sort Key: schema_0.testtab.entry" " -> Result (cost=7.09..65.05 rows=1101 width=8)" " -> Append (cost=7.09..65.05 rows=1101 width=8)" " -> Bitmap Heap Scan on testtab (cost=7.09..21.68 rows=367 width=8)" " Recheck Cond: (entry > 1000)" " -> Bitmap Index Scan on testtab_pkey (cost=0.00..7.00 rows=367 width=0)" " Index Cond: (entry > 1000)" " -> Bitmap Heap Scan on testtab (cost=7.09..21.68 rows=367 width=8)" " Recheck Cond: (entry > 1000)" " -> Bitmap Index Scan on testtab_pkey (cost=0.00..7.00 rows=367 width=0)" " Index Cond: (entry > 1000)" " -> Bitmap Heap Scan on testtab (cost=7.09..21.68 rows=367 width=8)" " Recheck Cond: (entry > 1000)" " -> Bitmap Index Scan on testtab_pkey (cost=0.00..7.00 rows=367 width=0)" " Index Cond: (entry > 1000)" -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
