| From: | Peter Eisentraut <peter_e(at)gmx(dot)net> |
|---|---|
| To: | Benedikt Grundmann <bgrundmann(at)janestreet(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: random_page_cost vs seq_page_cost |
| Date: | 2012-01-07 21:01:26 |
| Message-ID: | 1325970086.14090.1.camel@vanquo.pezone.net |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On tor, 2012-01-05 at 10:04 +0000, Benedikt Grundmann wrote:
> We have recently upgrade two of our biggest postgres databases
> to new hardware and minor version number bump (8.4.5 -> 8.4.9).
>
> We are experiencing a big performance regression in some queries.
> In those cases the planner seems to choose a nested loop index
> scan instead of hashing the index once and then joining.
There was a planner regression introduced in version 8.4.8, which was
thought to be fixed in 8.4.9. Maybe you got caught by that. See
Message-Id: <760C0206-B5F4-4DC6-9296-B7A730B7F403(at)silentmedia(dot)com>
for some information. Check if your queries match that pattern.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Peter Eisentraut | 2012-01-07 21:31:21 | return values of backend sub-main functions |
| Previous Message | Jeff Janes | 2012-01-07 19:19:04 | bgwriter holds onto file handles of deleted files |