high loads, fine tuning

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I have this server, Dual Intel Xeon 2.83GHz w 4gb ram.
My shared buffers were set to 1756 MB.

We have a high traffic e-commerce site, yesterday like 80000 uniques.
We cache most of our dynamic pages to disk so its wierd we are experience
really slow response times with postgresql.

Usually the number of simultaneous connections i monitor is around 8 to 10,
but yesterday night, maybe there was a spike in the traffic, it was going up
to 100, so the pages were taking like 15 seconds to render.

The wierd thing is that server is fine, i mean the load on the server itself
is not that high, but postgresql for some reason was slowing bad.

We upgraded the ram to 8 GB ram today, replicated some of the read-only
tables to another database to split the load.

Is there anything i can check to see whats causing this really? Im checking
pg_stat_activity, all processes are idle, yet the timeout is set low on the
configuration, i dont know why they sit there.

With 8 GB ram, im thinking of incresing the shared_buffer to 3.
Whats a good value for work_mem and temp memory?

Any advise appreciated, server running on RHEL 2.6.18-128.7.1.el5 x86_64

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I have this server, Dual Intel Xeon 2.83GHz w 4gb ram.<br>My shared buffers=
were set to 1756 MB.<br><br>We have a high traffic e-commerce site, yester=
day like 80000 uniques.<br>We cache most of our dynamic pages to disk so it=
s wierd we are experience really slow response times with postgresql.<br>
<br>Usually the number of simultaneous connections i monitor is around 8 to=
10, but yesterday night, maybe there was a spike in the traffic, it was go=
ing up to 100, so the pages were taking like 15 seconds to render.<br><br>
The wierd thing is that server is fine, i mean the load on the server itsel=
f is not that high, but postgresql for some reason was slowing bad.<br><br>=
We upgraded the ram to 8 GB ram today, replicated some of the read-only tab=
les to another database to split the load.<br>
<br>Is there anything i can check to see whats causing this really? Im chec=
king pg_stat_activity, all processes are idle, yet the timeout is set low o=
n the configuration, i dont know why they sit there.<br><br>With 8 GB ram, =
im thinking of incresing the shared_buffer to 3.<br>
Whats a good value for work_mem and temp memory?<br><br>Any advise apprecia=
ted, server running on RHEL 2.6.18-128.7.1.el5 x86_64<br>

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Aras Angelo [ Di, 29 September 2009 20:42 ] [ ID #2017422 ]

Re: high loads, fine tuning

Zitat von Aras Angelo <araskoktas [at] gmail.com>:

> I have this server, Dual Intel Xeon 2.83GHz w 4gb ram.
> My shared buffers were set to 1756 MB.
>
> We have a high traffic e-commerce site, yesterday like 80000 uniques.
> We cache most of our dynamic pages to disk so its wierd we are experience
> really slow response times with postgresql.
>
> Usually the number of simultaneous connections i monitor is around 8 to 10,
> but yesterday night, maybe there was a spike in the traffic, it was going up
> to 100, so the pages were taking like 15 seconds to render.

As far as i know the default for max_connections is "100" on many
Linux Distros. This would explain why your web-app is slow when
reaching this limit.

Regards

Andreas




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lst_hoe02 [ Di, 29 September 2009 21:07 ] [ ID #2017423 ]

Re: high loads, fine tuning

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Sorry i forgot to mention it, max cli setting is 500.

On Tue, Sep 29, 2009 at 12:07 PM, <lst_hoe02 [at] kwsoft.de> wrote:

> Zitat von Aras Angelo <araskoktas [at] gmail.com>:
>
> I have this server, Dual Intel Xeon 2.83GHz w 4gb ram.
>> My shared buffers were set to 1756 MB.
>>
>> We have a high traffic e-commerce site, yesterday like 80000 uniques.
>> We cache most of our dynamic pages to disk so its wierd we are experience
>> really slow response times with postgresql.
>>
>> Usually the number of simultaneous connections i monitor is around 8 to
>> 10,
>> but yesterday night, maybe there was a spike in the traffic, it was going
>> up
>> to 100, so the pages were taking like 15 seconds to render.
>>
>
> As far as i know the default for max_connections is "100" on many Linux
> Distros. This would explain why your web-app is slow when reaching this
> limit.
>
> Regards
>
> Andreas
>
>
>
>
> --
> Sent via pgsql-admin mailing list (pgsql-admin [at] postgresql.org)
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-admin
>

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Sorry i forgot to mention it, max cli setting is 500. <br><br><div class="gmail_quote">On Tue, Sep 29, 2009 at 12:07 PM, <span dir="ltr"><lst_hoe02 [at] kwsoft.de></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Zitat von Aras Angelo <araskoktas [at] gmail.com>:<div class="im">
<br>
<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
I have this server, Dual Intel Xeon 2.83GHz w 4gb ram.<br>
My shared buffers were set to 1756 MB.<br>
<br>
We have a high traffic e-commerce site, yesterday like 80000 uniques.<br>
We cache most of our dynamic pages to disk so its wierd we are experience<br>
really slow response times with postgresql.<br>
<br>
Usually the number of simultaneous connections i monitor is around 8 to 10,<br>
but yesterday night, maybe there was a spike in the traffic, it was going up<br>
to 100, so the pages were taking like 15 seconds to render.<br>
</blockquote>
<br></div>
As far as i know the default for max_connections is "100" on many Linux Distros. This would explain why your web-app is slow when reaching this limit.<br>
<br>
Regards<br>
<br>
Andreas<br><font color="#888888">
<br>
<br>
<br>
<br>
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</font></blockquote></div><br>

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Aras Angelo [ Di, 29 September 2009 21:12 ] [ ID #2017424 ]
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