Re: default resource limits

From: Andrew Dunstan <andrew(at)dunslane(dot)net>
To: "Patches (PostgreSQL)" <pgsql-patches(at)postgresql(dot)org>
Subject: Re: default resource limits
Date: 2005-12-23 20:50:10
Message-ID: 43AC6302.1070202@dunslane.net
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er patch attached this time

Andrew Dunstan wrote:

>
>
> I wrote:
>
>>
>>
>> Tom Lane wrote:
>>
>>> Andrew Dunstan <andrew(at)dunslane(dot)net> writes:
>>>
>>>
>>>> Nearly everyone seems to agree that the default for max_fsm_pages
>>>> is woefully low, so I would like to have the default for this set
>>>> unconditionally to 200,000 rather than 20,000. The cost would be
>>>> just over 1Mb of shared memory, if the docs are correct.
>>>> Alternatively, we could put this into the mix that is calculated by
>>>> initdb, scaling it linearly with shared_buffers (but with the
>>>> default still at 200,000).
>>>>
>>>
>>>
>>>
>>>
>>>
>>>> I would also like to propose a more modest increase in
>>>> max_connections and shared_buffers by a factor of 3.
>>>>
>>>
>>>
>>>
>>> I don't mind having initdb try larger values to see if they work, but
>>> if you are suggesting that we try to force adoption of larger settings
>>> I'll resist it.
>>>
>>>
>>
>> OK, works for me. The only thing I suggested might be set in stone
>> was max_fsm_pages; I always envisioned the others being tested as now
>> by initdb.
>>
>>> "Factor of three" seems mighty weird. The existing numbers (100 and
>>> 1000)
>>> at least have the defensibility of being round.
>>>
>>>
>>>
>>
>> What numbers would you like? If what I suggested seems odd, how about
>> targets of 400 connections, 4000 shared_buffers and 200,000
>> max_fsm_pages?
>>
>>
>
>
> Here's a patch that does what I had in mind. On my modest workstation
> it tops out at 400 connections and 2500/125000
> shared_buffers/max_fsm_pages. An idle postmaster with these settings
> consumed less than 4% of the 380Mb of memory, according to top, making
> it still dwarfed by X, mozilla, apache and amavisd among other memory
> hogs.
>
> Comments welcome.
>
> cheers
>
> andrew
>
> ---------------------------(end of broadcast)---------------------------
> TIP 5: don't forget to increase your free space map settings
>

Attachment Content-Type Size
revlimits.diff text/x-patch 3.3 KB

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