Re: [HACKERS] psql nested queries with 2000+ records

At 12:24 PM 3/20/98 -0500, Bruce Momjian wrote:

>Very strange.  15+ minutes?  Wow, that is terrible, even longer than a
>sequential scan of the table.  Try EXPLAIN and tell us what it says in
>the two cases.

This is within the 2717 record database.

explain select name from games where name in (select name from games where
name like 'A%');

NOTICE:  QUERY PLAN:

Seq Scan on games  (cost=207.95 size=446 width=12)
  SubPlan
    ->  Seq Scan on games  (cost=207.95 size=1 width=12)

NOTICE:  QUERY PLAN:

Seq Scan on games  (cost=207.95 size=446 width=12)
  SubPlan
    ->  Seq Scan on games  (cost=207.95 size=1 width=12)

EXPLAIN

This is within the 24 record database of the same type of data

explain select name from games where name in (select name from game
s where name like 'A%');
NOTICE:  QUERY PLAN:

Seq Scan on games  (cost=207.95 size=446 width=12)
  SubPlan
    ->  Seq Scan on games  (cost=207.95 size=1 width=12)

NOTICE:  QUERY PLAN:

Seq Scan on games  (cost=207.95 size=446 width=12)
  SubPlan
    ->  Seq Scan on games  (cost=207.95 size=1 width=12)

EXPLAIN

Obviously, I get the same information, any suggestions?

-Coronach@hill-b-073.resnet.purdue.edu