| From: | Matthew Wakeling <matthew(at)flymine(dot)org> |
|---|---|
| To: | Віталій Тимчишин <tivv00(at)gmail(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Very specialised query |
| Date: | 2009-03-30 16:22:15 |
| Message-ID: | alpine.DEB.2.00.0903301719230.21772@aragorn.flymine.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
On Mon, 30 Mar 2009, Віталій Тимчишин wrote:
> select
> case when n == 1 then id1 else id2 end,
> case when n == 2 then id1 else id2 end
>
> from (
> ... a, (values (1),(2)) b(n)
Yeah, that's nice.
However, it is still the case that we can't trust the database to choose
the correct plan. It is currently only choosing the correct plan now by
chance, and some time later it may by chance switch to one that takes 40
minutes.
I'll certainly add it to my list of possibilities.
Matthew
--
Jadzia: Don't forget the 34th rule of acquisition: Peace is good for business.
Quark: That's the 35th.
Jadzia: Oh yes, that's right. What's the 34th again?
Quark: War is good for business. It's easy to get them mixed up.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Scott Marlowe | 2009-03-30 16:25:36 | Re: Forcing seq_scan off for large table joined with tiny table yeilds improved performance |
| Previous Message | Віталій Тимчишин | 2009-03-30 16:14:30 | Re: Very specialised query |