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=13824000000width=8) -> Nested Loop (cost=0.00..115292.00 rows=5760000 width=8) -> Seq Scan on a
(cost=0.00..34.00rows=2400 width=4) -> Materialize (cost=0.00..82.00 rows=2400 width=4) -> Seq
Scanon b (cost=0.00..34.00 rows=2400 width=4) -> Materialize (cost=0.00..82.00 rows=2400 width=0) -> Seq
Scanon c (cost=0.00..34.00 rows=2400 width=0)
(7 rows)
Regards
Pavel Stehule
