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Thread: full vacuum - resources - scaling

full vacuum - resources - scaling

From
"Mr. Dan"
Date:
Hi,

I have noticed that my full vacuum and re-index script is taking a day and a
half instead of 1/2 day.
Recently, the size of my database cluster has doubled to 130 GB.   Would
anyone recommend increasing one or more of these to help get my full vacuums
to run a little faster?

Thanks,
~DjK



work memory       49152 KB
shared buffers      65536 (8 KB)
maxfsmpages       480001 (6 bytes each)
maxfsmrelations    30000 (70 bytes each)

effective cache     983040 (8 KB each)

Re: full vacuum - resources - scaling

From
Alvaro Herrera
Date:
Mr. Dan wrote:
> Hi,
>
> I have noticed that my full vacuum and re-index script is taking a day and
> a half instead of 1/2 day.
> Recently, the size of my database cluster has doubled to 130 GB.   Would
> anyone recommend increasing one or more of these to help get my full
> vacuums to run a little faster?

I guess the question is why are you running vacuum full at all.  Plain
vacuum should suffice, provided the FSM settings are enough for your
database:

> maxfsmpages       480001 (6 bytes each)
> maxfsmrelations    30000 (70 bytes each)

max_fsm_pages at 480000 are enough to cover 3 GB, if my math is correct.
It may be enough or it may not, depending on the dynamics of your data.

Also with non-full vacuum you may be able to get away with vacuuming
some tables more often.

--
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.

Re: full vacuum - resources - scaling

From
Andrew Sullivan
Date:
On Tue, May 30, 2006 at 09:44:22AM -0400, Mr. Dan wrote:
> Hi,
>
> I have noticed that my full vacuum and re-index script is taking a day and
> a half instead of 1/2 day.
> Recently, the size of my database cluster has doubled to 130 GB.   Would
> anyone recommend increasing one or more of these to help get my full
> vacuums to run a little faster?

What Alvaro said.  I'll also point out, however, that in my
experience, VACUUM FULL time does not increase linearly with database
size.  I suspect this is because of the cost of reorganising so much
more data, but I haven't done any real analysis of it.

The main thing is, "Don't do vacuum full."

A
--
Andrew Sullivan  | ajs@crankycanuck.ca
The whole tendency of modern prose is away from concreteness.
        --George Orwell