> -----Original Message----- > From: pgsql-hackers-ow...@postgresql.org [mailto:pgsql-hackers- > ow...@postgresql.org] On Behalf Of Pavel Stehule > Sent: Monday, January 11, 2010 11:55 PM > To: PostgreSQL Hackers > Cc: Tom Lane > Subject: [HACKERS] planner or statistical bug on 8.5 > > Hello > > I checked query and I was surprised with very strange plan: > > postgres=# create table a(a int primary key); > NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index > "a_pkey" for table "a" > CREATE TABLE > postgres=# create table b(b int primary key); > NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index > "b_pkey" for table "b" > CREATE TABLE > postgres=# create table c(c int primary key); > NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index > "c_pkey" for table "c" > CREATE TABLE > postgres=# ANALYZE ; > ANALYZE > postgres=# explain select a, b from a,b,c; > QUERY PLAN > ----------------------------------------------------------------------- > Nested Loop (cost=0.00..276595350.00 rows=13824000000 width=8) > -> Nested Loop (cost=0.00..115292.00 rows=5760000 width=8) > -> Seq Scan on a (cost=0.00..34.00 rows=2400 width=4) > -> Materialize (cost=0.00..82.00 rows=2400 width=4) > -> Seq Scan on b (cost=0.00..34.00 rows=2400 width=4) > -> Materialize (cost=0.00..82.00 rows=2400 width=0) > -> Seq Scan on c (cost=0.00..34.00 rows=2400 width=0) > (7 rows)
You have no join columns, so it is a simple product. Perhaps you meant something like this: EXPLAIN SELECT a.a, b.b, c.c FROM a a, b b, c c WHERE a.a = b.b AND a.a = c.c -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers