From: Richard Huxton <dev@archonet.com>
To: Din Adrian <adrian.din@easynet.ro>
Cc: pgsql-sql@postgresql.org
Subject: Re: [PERFORM] Tunning postgresql on linux (fedora core 3)
Date: Thu, 03 Feb 2005 15:15:32 +0000
Message-ID: <42024014.2030901@archonet.com> (raw)
In-Reply-To: <opslmr5qxxawcxfg@adi>
References: <opsll8h2shawcxfg@adi>
<420202D0.7070602@archonet.com>
<opslmno9cpawcxfg@adi>
<42022DA2.3040000@archonet.com>
<opslmpx0u3awcxfg@adi>
<42023A94.5040904@archonet.com>
<opslmr5qxxawcxfg@adi>
Din Adrian wrote:
> 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
It's not that it's incorrect, just that you should always use the
manuals as a starting point.
> On Thu, 03 Feb 2005 14:52:04 +0000, Richard Huxton <dev@archonet.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@archonet.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
>>
>
>
>
--
Richard Huxton
Archonet Ltd
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To: pgsql-sql@postgresql.org
Cc: dev@archonet.com, adrian.din@easynet.ro
Subject: Re: [PERFORM] Tunning postgresql on linux (fedora core 3)
In-Reply-To: <42024014.2030901@archonet.com>
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