From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
---|---|
To: | PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Subject: | planner or statistical bug on 8.5 |
Date: | 2010-01-12 07:55:10 |
Message-ID: | 162867791001112355o55b61b85t42bdf8b9271eb981@mail.gmail.com |
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Lists: | pgsql-hackers |
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)
Regards
Pavel Stehule
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