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From "Filip Hanik \(mailing lists\)" <devli...@hanik.com>
Subject RE: Tomcat 7.0.28 connection pool issue
Date Thu, 28 Jun 2012 20:41:39 GMT
Martin, generally I would run with fairQueue="false" - this is the default.
The only time I would change to fairQueue="true" is if we see threads being
starved, and not getting connections. However, this scenario is very
unlikely unless there is extreme concurrency going on.

Filip

> -----Original Message-----
> From: Martin Gainty [mailto:mgainty@hotmail.com]
> Sent: Thursday, June 28, 2012 1:38 PM
> To: Tomcat Users List
> Subject: RE: Tomcat 7.0.28 connection pool issue
> 
> 
> Hi Filip
> 
> Is there an algorithm we can use to determine if the op should configure
> concurrent db connections (fairQueue=false)  vs config non-concurrent db
> connections (fairQueue=true)
> e.g. if 50%+ of database cursors are 'read-only' then concurrent
> connections *should be used* and TC attribute of fairQueue should be set
> to false
> Thanks!
> Martin
> ______________________________________________
> Place legal disclaimer here
> 
>  > From: devlists@hanik.com
> > To: users@tomcat.apache.org
> > Subject: RE: Tomcat 7.0.28 connection pool issue
> > Date: Thu, 28 Jun 2012 11:36:49 -0600
> >
> > Then the issue you may be running into is that your Tomcat
> configuration
> > supports a higher concurrency level than what your Resin configuration
> is
> > setup to do.
> > With higher concurrency, there will be a need for more data base
> > connections. If you still want to run with a lower number of
> connections,
> > what you can do is set
> >
> > fairQueue="true"
> > maxWait="time in milliseconds to wait for next available connection"
> >
> > and what this effectively will do, is lower your concurrency.
> Recommended is
> > of course to increase maxActive if the database supports it.
> >
> > Filip
> >
> >
> > > -----Original Message-----
> > > From: Yasser [mailto:yarafatin@gmail.com]
> > > Sent: Thursday, June 28, 2012 11:33 AM
> > > To: Tomcat Users List
> > > Subject: Re: Tomcat 7.0.28 connection pool issue
> > >
> > > That was the issue with Tomcat 7.0.26 and they fixed it in 7.0.28
> > >
> > >
> > > On Thu, Jun 28, 2012 at 11:54 AM, Filip Hanik (mailing lists) <
> > > devlists@hanik.com> wrote:
> > >
> > > > Could you have run into
> > > > https://issues.apache.org/bugzilla/show_bug.cgi?id=53367
> > > >
> > > > ?
> > > >
> > > > You could try out
> > > > http://people.apache.org/~fhanik/jdbc-pool/bz53367-jdbc-pool.jar
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Yasser [mailto:yarafatin@gmail.com]
> > > > > Sent: Thursday, June 28, 2012 9:39 AM
> > > > > To: Tomcat Users List
> > > > > Subject: Re: Tomcat 7.0.28 connection pool issue
> > > > >
> > > > > Yes. It does show that maxactive has reached 100. I also use
> splunk
> > > to
> > > > > get
> > > > > the connection status at the oracle side.
> > > > > What I dont understand is that Resin needs just 50 connections
> to
> > > handle
> > > > > the same load. I am in the process of increasing the count to
> 300
> > > and
> > > > > see
> > > > > if that makes a difference. Oracle has the capacity to handle
> that
> > > many
> > > > > connections.
> > > > >
> > > > >
> > > > > On Thu, Jun 28, 2012 at 11:01 AM, Hedrick, Brooke - 43 <
> > > > > brooke.hedrick@rainhail.com> wrote:
> > > > >
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Yasser [mailto:yarafatin@gmail.com]
> > > > > > > Sent: Thursday, June 28, 2012 9:44 AM
> > > > > > > To: users@tomcat.apache.org
> > > > > > > Subject: Tomcat 7.0.28 connection pool issue
> > > > > > >
> > > > > > ...
> > > > > > > What is the issue?
> > > > > > > When we run a stress test on the same codebase deployed
to
> > > Tomcat
> > > > > 7.0.28,
> > > > > > > at about 2hr45min into the test with 530 virtual users
> logged in
> > > (at
> > > > > > peak load),
> > > > > > > I get a lot of connection pool empty errors. The maxactive
> > > attribute
> > > > > > (using
> > > > > > > tomcat connection pool) has been set to 100.
> > > > > > >
> > > > > >
> > > > > > Have you used jconsole to monitor the pool usage?
> > > > > >
> > > > > > -Brooke
> > > > > >
> > > > > > > Other information:
> > > > > > > CAS runs on a different server with a dedicated tomcat
home
> and
> > > > > base. I
> > > > > > > dont see any errors on this box.
> > > > > > > 7.0.26 was found to have a bug in the way connection count
> is
> > > > > determined,
> > > > > > > which got fixed in 7.0.28, hence we switched to the latest
> > > version.
> > > > > > >
> > > > > > > Here is one of the connection pool config from server.xml.
> We do
> > > a
> > > > > > resource
> > > > > > > link to this pool in the context.xml
> > > > > > >
> > > > > > > <Resource name="jdbc/global-wl" auth="Container"
> > > > > > >         type="javax.sql.DataSource" username="webconnect"
> > > > > > > password="xxxxxxx"
> > > > > > >         driverClassName="oracle.jdbc.driver.OracleDriver"
> > > > > > >
> > > > > > >
> > > url="jdbc:oracle:thin:@&&dbs.ip&&:&&oracle.db.port&&:&&dts.dbname&&
> > > > > > > "
> > > > > > >
> > > factory="org.apache.tomcat.jdbc.pool.DataSourceFactory"
> > > > > > >         maxActive="100" />
> > > > > > >
> > > > > > > Any help is appreciated. Please let me know if you need
more
> > > > > information
> > > > > > or
> > > > > > > code snippets.
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Yasser
> > > > > >
> > > > > > --------------------------------------------------------------
> ----
> > > ---
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> > > > > >
> > > > > >
> > > >
> > > >
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> > > >
> > > >
> >
> >
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> 


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