[daisy] connection pool exhausted

[Bruno Dumon]

On Tue, 2007-03-06 at 17:09 +0100, Tom Brusselle wrote:
> Bruno Dumon wrote:
> > 
> > Yes, this can be done in the myconfig.xml. The number of connections
> > doesn't need to be much higher than the number of concurrent users
> > though.
> 
> Exactly what parameter should i be looking at?  i found only the 
> following entries.  Could it be that i'm running into this maxActive limit?

That's indeed the limit you're running into.

>    (20 concurrent users editing a page could be possible, 20 users 
> concurrently requesting or saving a page would be very unlikely and very 
> quickly resolved, 5000 concurrent users would not be possible)

Yes indeed.

> 
>    <target path="/daisy/datasource/datasource">
>      <configuration>
> ...
>        <maxActive>20</maxActive>
>        <maxIdle>8</maxIdle>
>        <minIdle>0</minIdle>
>        <maxWait>5000</maxWait>
>      </configuration>
>    </target>
> 
> 
> > 
> >>    (or could it is possible that connections somehow don't get 
> >> released over time and that's wy we eventually run out?)
> > 
> > Seems like connections are leaking somewhere, it would be interesting to
> > know where. Is the Daisy repository server customized in some way? (such
> > as a custom authentication scheme).
> 
> no, we're using a standard daisy 1.5.1, with the built in daisy 
> authentication scheme.  The only customizations are the fact that we run 
> daisy under tomcat and that we use non-default ports.

ok, I just wanted to rule out that possibility.

> 
> I'd also like to see where the connections are going but i'm not a big 
> java debugger/devoloper so if that's possible please let me me how.
> 

The connection pool we use (Jakarta commons DBCP) has a feature to log a
stack trace of where "abandoned connections" (= connections not released
after a certain timeout) were obtained. I have no experience using it,
and it requires a change in Daisy to be able to activate it.

If you can easily reproduce this error, I could look into supplying you
an updated daisy-datasource jar in which this logging feature is
enabled.

Or you can look into doing it yourself: the code is in the Daisy source
tree in services/datasource, you only need to recompile that subproject
and throw the resulting jar over the corresponding one in your Daisy
install.

-- 
Bruno Dumon                             http://outerthought.org/
Outerthought - Open Source, Java & XML Competence Support Center
bruno at outerthought.org                          bruno at apache.org