| From: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
|---|---|
| To: | Jim Nasby <decibel(at)decibel(dot)org> |
| Cc: | Josh Berkus <josh(at)agliodbs(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: 8.2 is 30% better in pgbench than 8.3 |
| Date: | 2007-07-23 17:54:32 |
| Message-ID: | 20070723175431.GA4213@alvh.no-ip.org |
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| Thread: | |
| Lists: | pgsql-hackers |
Jim Nasby wrote:
> On Jul 22, 2007, at 8:54 AM, Josh Berkus wrote:
>> Tom,
>>> Note to all: we ***HAVE TO*** settle on some reasonable default
>>> vacuum_cost_delay settings before we can ship 8.3. With no cost delay
>>> and two or three workers active, 8.3's autovac does indeed send
>>> performance into the tank.
>>
>> I've been using 20ms for most of my setups. That's aimed at reducing
>> autovac to almost no impact at all, but taking a long time. Maybe 10ms?
>
> I've found 20ms to be a pretty good number for run-of-the-mill IO
> capability, and 10ms to be good for a good RAID setup (RAID10, 8+ drives,
> BBU).
>
> For a default setting, I think it'd be better to lean towards 20ms.
OK, 20ms it is then. Here is a patch. I am taking the liberty to also
lower the vacuum and analyze threshold default values to 50, per
previous discussion.
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
| Attachment | Content-Type | Size |
|---|---|---|
| autovac-params.patch | text/x-diff | 3.4 KB |
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