| From: | Dirk Lutzebaeck <lutzeb(at)aeccom(dot)com> |
|---|---|
| To: | pgsql-general(at)hub(dot)org |
| Subject: | Re: performance and number of selected columns |
| Date: | 2000-05-22 15:56:02 |
| Message-ID: | 14633.22674.316652.283601@ampato.core.aeccom.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
Dirk Lutzebaeck writes:
>
> Hi,
>
> say I have three tables a,b,c with lots of columns (say 10 for each
> table). Using psql command line, why does
>
> SELECT a.*,b.*,c.* FROM a,b,c
>
> takes much more longer (in my specifc case 3 times) than only
> selecting one column like
>
> SELECT a.oid, b.oid, c.oid FROM a,b,c.
>
> This is on 7.0. Can I play with buffer sizes? Indexes exist on most
> of the columns. Columns in the second line can be arbitrary.
Two things two add:
- EXPLAIN shosw the same results in both cases
- currently I was working with ~ 500 rows
Dirk
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Ron Peterson | 2000-05-22 15:57:03 | Re: Re: [HACKERS] Postgresql OO Patch |
| Previous Message | Barry Lind | 2000-05-22 15:43:57 | How do you rebind/reexecute a query without reparsing it? |