I have narrowed down part of the problem to the following exception
being thrown
java.util.ConcurrentModificationException
[dbPool] at java.util.HashMap$HashIterator.next(HashMap.java:736)
[dbPool] at
java.util.AbstractCollection.addAll(AbstractCollection.java:317)
[dbPool] at java.util.HashSet.<init>(HashSet.java:86)
[dbPool] at
org.opentools.minerva.pool.ObjectPool.runGCandShrink(ObjectPool.java:749
)
[dbPool] at
org.opentools.minerva.pool.PoolGCThread.runGC(PoolGCThread.java:66)
[dbPool] at
org.opentools.minerva.pool.PoolGCThread.run(PoolGCThread.java:37)
Can anyone give me a hint as to where to begin debugging this. The app
is under moderate load.
Dan
-----Original Message-----
From: Fred Loney [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, September 25, 2001 1:50 PM
To: [EMAIL PROTECTED]
Subject: Re: [JBoss-user] JBoss and MySql Problems
I agree that low pool size is useful for development; I set it to 2 for
that reason. Perhaps a simpler solution than intelligent self-tuning
algorithms is documentation: a prescriptive appendix that complements
the excellent descriptive documentation. E.g. a section of the HOWTO
chapter:
How to Tune JBoss
-------------------
For development ...
For testing ...
For production ...
I don't know enough about jboss to do this myself, but I would be
willing to collect the insights of others and write something up if that
would be of value.
Fred Loney
Spirited Software, Inc.
www.spiritedsw.com
----- Original Message -----
From: "David Jencks" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, September 25, 2001 5:20 AM
Subject: Re: [JBoss-user] JBoss and MySql Problems
> On 2001.09.24 23:04:00 -0400 marc fleury wrote:
> > |Let me say it again, louder: PUT A REASONABLE MAXSIZE IN YOUR POOL!
> >
> > can't we increase the max value in the default jcml?
> >
> > marcf
>
> Sure, but why? I'd rather eliminate the possibility of unlimited size.
I
> don't know hsql's max capabilities, but possibly 10 connections is
about
> all you'd want for a db running in the same vm as the server... with a
> bigger db, you can set for more.
>
> Right now, I kind of like a small default: many people are finding
ways to
> break connections/pooling, and I think it's good to make this show up
> soon.. so their app won't work, quickly, under very mild stress. Once
they
> fix it, they can adjust the pooling to match their load. What would
be
> great would be an estimator.... for x concurrent clients in a typical
web
> app w/ y db requests/ web page try z max connections...sigh, I fear
that's
> a long way off... maybe we could collect time/db call and average
blocking
> wait times to help... so much to do. Does something like this relate
in
> any way to the stuff Andy was working on?
>
> david jencks
> >
> > |If your app doesn't work well with a fairly small value
proportional to
> > |the
> > |load on your app, there is something wrong that you need to fix.
> > |
> > |david jencks
> > |
> > |> Thanks,
> > |> Dan
> > |>
> > |> -----Original Message-----
> > |> From: David Jencks [mailto:[EMAIL PROTECTED]]
> > |> Sent: Monday, September 24, 2001 6:37 PM
> > |> To: [EMAIL PROTECTED]
> > |> Subject: Re: [JBoss-user] JBoss and MySql Problems
> > |>
> > |>
> > |> Well, setting maxsize to 0 means no limit. Some db/driver
> > |combinations
> > |> have a limit on the number of concurrent connections, at least
from
> > |one
> > |> ip
> > |> address. Try setting maxsize rather small -- say 5 or 10 -- and
> > |verify
> > |> you
> > |> really are releasing connections.
> > |>
> > |> david jencks
> > |>
> > |> On 2001.09.24 18:00:22 -0400 Daniel Ferrante wrote:
> > |> > Hi -
> > |> > Below is my setup for a connection pool with mysql. I am using
CMP
> > |> with
> > |> > JBoss and MySQL
> > |> >
> > |> > <mbean code="org.jboss.jdbc.XADataSourceLoader"
> > |> > name="DefaultDomain:service=XADataSource,name=dbPool">
> > |> > <attribute name="PoolName">dbPool</attribute>
> > |> > <attribute
> > |> >
> > |>
> >
|name="DataSourceClass">org.opentools.minerva.jdbc.xa.wrapper.XADataSour
c
> > |> > eImpl</attribute>
> > |> > <attribute name="URL">jdbc:mysql:url</attribute>
> > |> > <attribute name="JDBCUser">user</attribute>
> > |> > <attribute name="Blocking">true</attribute>
> > |> > <attribute name="MaxSize">0</attribute>
> > |> > <attribute name="Password">pass</attribute>
> > |> > <attribute name="LoggingEnabled">true</attribute>
> > |> > </mbean>
> > |> >
> > |> > I am trying to debug why my application constantly dies (or
hangs)
> > |> after
> > |> > 100 connections are created. I have made sure that I am
closing all
> > |> the
> > |> > connections to the database in my code (that is anywhere I make
a
> > |> direct
> > |> > connection to the database not using the entity beans).
> > |> >
> > |> > I understand since Blocking is set to true that it waits for a
new
> > |> > connection. Is this a problem with CMP, mySQL, or do you see
> > |anything
> > |> > in the XADataSourceLoader.
> > |> >
> > |> > Thanks
> > |> > Dan
> > |> >
> > |> > _______________________________________________
> > |> > JBoss-user mailing list
> > |> > [EMAIL PROTECTED]
> > |> > https://lists.sourceforge.net/lists/listinfo/jboss-user
> > |> >
> > |> >
> > |>
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> > |
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