Re: 10.2.0.4 / New Hugepages / JDBC Thin connections slow connect ?
- From: Nuno Souto <dbvision@xxxxxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Wed, 26 Jun 2013 20:35:53 +1000
With hugepages and assuming no use of AMM - yes, I know in some OS hugepages
and AMM are incompatible, stay with me here until the end of the paragraph! -
the SGA is reserved in one go. That doesn't mean *ALL* memory structures will
be pre-filled: they may well not be referenced for a while. Doesn't mean they
don't get reserved.
In Aix and without AMM, the reservation of hugepages is immediate on startup
and it doesn't budge until shutdown. I don't know what happens with AMM as I
refuse to use it.
--
Cheers
Nuno Souto
dbvision@xxxxxxxxxxxx
On 26/06/2013 1:58 AM, Christopher.Taylor2@xxxxxxxxxxxx wrote:
> I thought that was AIX (others?) specific but that's a good question. Seems
> like I read that AIX does that but not positive.
>
> Actually, I know for sure that it doesn't on Linux because it RESERVES
> hugepages but doesn't use them - you can watch the free hugepages count go
> down as Oracle claims memory I believe. I'll try to verify on my end however.
>
> Chris
>
>
> -----Original Message-----
> From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
> Behalf Of Josh Collier
> Sent: Tuesday, June 25, 2013 10:34 AM
> To: oracle-l@xxxxxxxxxxxxx
> Subject: RE: 10.2.0.4 / New Hugepages / JDBC Thin connections slow connect ?
>
> When you have enabled huge pages, and verified that your SGA is going into
> the huge pages pool, Doesn't the SGA get pre-paged regardless of this
> particular parameter (pre_page_sga)?
>
> The way I understand it, with huge pages enabled, the SGA is loaded(paged-in)
> completely on instance startup. Do I have a misunderstanding?
>
> Josh C
>
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