Message-ID: <4C7BB7D0.3010201@nasa.gov>
Date: Mon, 30 Aug 2010 09:53:20 -0400
From: "Maria L. Wilson" <Maria.L.Wilson-1@nasa.gov>
Reply-To: <Maria.L.Wilson-1@nasa.gov>
Organization: SSAI
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To: Scott Marlowe <scott.marlowe@gmail.com>
CC: "Wilson, Maria Louise (LARC-E301)[SCIENCE SYSTEMS APPLICATIONS]"
	<m.l.wilson@nasa.gov>, "pgsql-performance@postgresql.org"
	<pgsql-performance@postgresql.org>
Subject: Re: [Fwd: postgres 8.4.1 number of connections]
References: <4C76CEAB.1070308@nasa.gov>
	<AANLkTikkCJ1embk=i6V06k7sRQqv3WfGGwPLNGTGuMWV@mail.gmail.com>
In-Reply-To: <AANLkTikkCJ1embk=i6V06k7sRQqv3WfGGwPLNGTGuMWV@mail.gmail.com>
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thanks for your response....
we have 3 app servers that attach to this one particular database server.
What kind of load issues did you find on 8.4.1?  I'd be interested in 
anything documented on it - this might make an upgrade a higher priority!

thanks,  Maria

Scott Marlowe wrote:
> On Thu, Aug 26, 2010 at 2:29 PM, Maria L. Wilson
> <Maria.L.Wilson-1@nasa.gov> wrote:
>   
>> we have this application (using jboss/java/hibernate) on linux accessing
>> data on 3 postgres database servers using 8.4.1.
>>
>> One of our many concerns has been the way we handle connections to the
>> database.  java/hibernate handle their own pooling so I understand that
>> using anything else is out of the question.
>>     
>
> It's not impossible to put another connection pooler between hibernate
> and your database server.  May not be useful or better, but it's
> possible.
>
>   
>>  Our jboss configuration
>> currently defaults to 5 connections per database.
>>     
>
> I assume this is for each app server.  How many app servers do you have?
>
>   
>>  On our main database
>> server, we handle 7 of the databases that this application uses.  On
>> this one server, we usually average around 300 - 500 connections to the
>> server.  In our postgres conf file on this particular machine we set the
>> max_connection parameter to 1000.  If we set it to much lower we end up
>> with connection errors.  Any comments or better way to handle this?
>>     
>
> Other than breaking out the databases onto their own server, or trying
> to pool to fewer connections, not really.  OTOH, a db server with
> enough memory can handle having that many connections as long as you
> don't run into any thundering herd issues.
>
> Oh, and you should really update your pgsql to 8.4.4.  8.4.1 had some
> issues with heavy load I ran into last year about this time.  Which is
> why I'm still on 8.3.11
>
> --
> To understand recursion, one must first understand recursion.
>   

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thanks for your response....<br>
we have 3 app servers that attach to this one particular database
server.<br>
What kind of load issues did you find on 8.4.1?&nbsp; I'd be interested in
anything documented on it - this might make an upgrade a higher
priority!<br>
<br>
thanks,&nbsp; Maria<br>
<br>
Scott Marlowe wrote:
<blockquote
 cite="mid:AANLkTikkCJ1embk=i6V06k7sRQqv3WfGGwPLNGTGuMWV@mail.gmail.com"
 type="cite">
  <pre wrap="">On Thu, Aug 26, 2010 at 2:29 PM, Maria L. Wilson
<a class="moz-txt-link-rfc2396E" href="mailto:Maria.L.Wilson-1@nasa.gov">&lt;Maria.L.Wilson-1@nasa.gov&gt;</a> wrote:
  </pre>
  <blockquote type="cite">
    <pre wrap="">
we have this application (using jboss/java/hibernate) on linux accessing
data on 3 postgres database servers using 8.4.1.

One of our many concerns has been the way we handle connections to the
database.  java/hibernate handle their own pooling so I understand that
using anything else is out of the question.
    </pre>
  </blockquote>
  <pre wrap=""><!---->
It's not impossible to put another connection pooler between hibernate
and your database server.  May not be useful or better, but it's
possible.

  </pre>
  <blockquote type="cite">
    <pre wrap=""> Our jboss configuration
currently defaults to 5 connections per database.
    </pre>
  </blockquote>
  <pre wrap=""><!---->
I assume this is for each app server.  How many app servers do you have?

  </pre>
  <blockquote type="cite">
    <pre wrap=""> On our main database
server, we handle 7 of the databases that this application uses.  On
this one server, we usually average around 300 - 500 connections to the
server.  In our postgres conf file on this particular machine we set the
max_connection parameter to 1000.  If we set it to much lower we end up
with connection errors.  Any comments or better way to handle this?
    </pre>
  </blockquote>
  <pre wrap=""><!---->
Other than breaking out the databases onto their own server, or trying
to pool to fewer connections, not really.  OTOH, a db server with
enough memory can handle having that many connections as long as you
don't run into any thundering herd issues.

Oh, and you should really update your pgsql to 8.4.4.  8.4.1 had some
issues with heavy load I ran into last year about this time.  Which is
why I'm still on 8.3.11

--
To understand recursion, one must first understand recursion.
  </pre>
</blockquote>
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