Thread: Re: [GENERAL] Huge Pages - setting the right value

We are experiencing some performance issues because of high CPU load. So I
would like to ask one more time. The exact question is:
Does PostgreSQL can use huge pages for processes or only for shared buffers?
(Does it make any sense to set the number of huge pages above the
shared_buffers?)
Any help or suggestions would be much appreciated!



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I can't give you an absolutely authoritative answer, but because of the way hugepages are implemented and allocated, I
can'tthink how they could be used for other processes.  Linux hugepages are either 2m or 1g, far too large for any
likelyprocesses to require. They cannot be allocated in partial pages. 

Sent from my iPad

> On Jun 11, 2017, at 10:02 AM, pinker <pinker@onet.eu> wrote:
>
> We are experiencing some performance issues because of high CPU load. So I
> would like to ask one more time. The exact question is:
> Does PostgreSQL can use huge pages for processes or only for shared buffers?
> (Does it make any sense to set the number of huge pages above the
> shared_buffers?)
> Any help or suggestions would be much appreciated!
>
>
>
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> View this message in context:
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>
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Andrew Kerber wrote
> I can't give you an absolutely authoritative answer, but because of the
> way hugepages are implemented and allocated, I can't think how they could
> be used for other processes.  Linux hugepages are either 2m or 1g, far too
> large for any likely processes to require. They cannot be allocated in
> partial pages.

thank you for your help.
My system is using 2MB pages for shared buffers. I have checked and one of
my processes has used 606788kB of memory, so potentially could use ~ 300
huge pages, but does postgres can use it for non shared memory?




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I am sure it does not.

Sent from my iPhone

> On Jun 11, 2017, at 10:50 AM, pinker <pinker@onet.eu> wrote:
>
> Andrew Kerber wrote
>> I can't give you an absolutely authoritative answer, but because of the
>> way hugepages are implemented and allocated, I can't think how they could
>> be used for other processes.  Linux hugepages are either 2m or 1g, far too
>> large for any likely processes to require. They cannot be allocated in
>> partial pages.
>
> thank you for your help.
> My system is using 2MB pages for shared buffers. I have checked and one of
> my processes has used 606788kB of memory, so potentially could use ~ 300
> huge pages, but does postgres can use it for non shared memory?
>
>
>
>
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> View this message in context:
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>
>
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standard hugepages, transparent are disabled.
They were set exactly following the procedure from postgres documentation.



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