Re: [PERFORM] Tunning postgresql on linux (fedora core 3)

From: Din Adrian <adrian(dot)din(at)easynet(dot)ro>
To: "Richard Huxton" <dev(at)archonet(dot)com>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: [PERFORM] Tunning postgresql on linux (fedora core 3)
Date: 2005-02-03 16:59:40
Message-ID: opslmr5qxxawcxfg@adi
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sorry about cc ...
this is the site:
http://www.varlena.com/varlena/GeneralBits/Tidbits/annotated_conf_e.html
but I gues is not right ... hmm

Adrian Din

On Thu, 03 Feb 2005 14:52:04 +0000, Richard Huxton <dev(at)archonet(dot)com>
wrote:

> I'll repeat myself:
>
>
>
>
> Please CC the mailing list as well as replying to me, so that others
> can help too.
>
>
>
>
> Din Adrian wrote:
>> On Thu, 03 Feb 2005 13:56:50 +0000, Richard Huxton <dev(at)archonet(dot)com>
>> wrote:
>>
>>> Please CC the mailing list as well as replying to me, so that others
>>> can help too.
>>>
>>>
>>>> b) in docs say that after 7.2 seting this to false does'n turn off
>>>> the wall ...!? wich option does?
>>>
>>>
>>> The docs don't say that, as far as I can see. It doesn't make sense
>>> to turn off the WAL.
>> hmm this is the doc about ...
>> ' NOTE: Since 7.2, turning fsync off does NOT stop WAL. It does stop
>> checkpointing, however. This is a change in the notes that follow Turn
>> WAL off (fsync=false) only for a read-only database or one where the
>> database can be regenerated from external software. While RAID plus
>> UPSes can do a lot to protect your data, turning off fsync means that
>> you will be restoring from backup in the event of hardware or power
>> failure.'
>
> I don't know what this is, and you don't give a URL, but it DOES NOT
> appear to be in the manuals.
>
> You should probably read the sections of the manuals regarding "run-time
> configuration" and "write ahead logs". The manuals are quite extensive,
> are available online at http://www.postgresql.org/ and also in most
> distributions.
>
> This is probably a good place to start.
> http://www.postgresql.org/docs/8.0/interactive/runtime-config.html#RUNTIME-CONFIG-WAL
>
>> If you turn it off you should have more speed ... !!!???
>
> Basically, as I said in my last email - fsync=true makes sure
> transaction details are safely stored on disk. If you turn this off, the
> database doesn't have to wait for the data to physically be written to
> the disk. But, if power fails then data might be in OS or disk cache and
> so lost when you restart the machine.
>
> Please CC the mailing list if you reply to this message.
> --
> Richard Huxton
> Archonet Ltd
>

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