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From Jesse Klaasse <jesse.klaa...@indicia.nl>
Subject Re: IIS 6.0 / JK1.2.25 / Tomcat 5.5.20 - "Service temporary unavailable"
Date Thu, 10 Jul 2008 09:34:55 GMT

Hi Rainer,

We are a week later now, with the changed settings, and while the
environment first seemed to be a little more stable, in the end this
unfortunately is not the case... We still reboot Tomcat every night
automatically, and most of the time once a day manually because of the 503
error.

For example, I restarted Tomcat and IIS 10 minutes ago, and in the last 10
minutes, isapi_redirect.log shows about 7 503 errors. Also a lot of 53, 54,
60 and 61 errors.

Still looking into the dbcp issue.. I will try to put up a new post, but I'm
not sure what the relevant info would be..

Do you have any clues left?

Regards, Jesse.





Rainer Jung-3 wrote:
> 
> Hi Jesse,
> 
> Jesse Klaasse wrote:
>> Hello Rainer,
>> 
>> Thanks again for your prompt and clear reply. You're helping me a lot!
>> 
>> I have implemented the settings as you suggested (for the datasources of
>> all
>> 8 webapps on my Tomcat server). I need to wait for a restart of the
>> application before the settings become active, however.
>> For your information: currently (Tomcat is running fine now) a netstat
>> command returns about 30 established connections to the database server.
>> I
>> have lowered the removeAbandonedTimeout setting to 30 seconds instead of
>> 60.
> 
> ... and the 30 seconds are already active (restart done) or also only 
> after the next restart ...
> 
>> I still have a few questions left;
>> 
>> Why are there no 'AbandonedObjectPool' messages at all when Tomcat is
>> running fine? I would expect a slowly growing number of locked threads
>> because of the AbandonedObjectPool. But this not happening. Does this
>> maybe
>> mean that once it goes wrong, it skyrockets up to the total of 400 locked
>> threads? And why would that be?
> 
> By message we mean methods in the thread stacks contained in a thread
> dump?
> 
> Usually getConnection() is a very fast method. So it will be hard to 
> find a thread in there unless the getConnection() triggers a new 
> connection establishment to the database (which again might only take a 
> handful of milliseconds), or the pool is exhausted and getConnection() 
> goes into the maxWait.
> 
> So yes, I would expect, that if one getConnection() hangs seriously, 
> i.e. needs to wait long for actually getting a connection, then very 
> soon a lot of threads will get into this state. Depending on your load, 
> it's possible that e.g. you are calling getConnection() 100 times per 
> second. So if the pool is full for a couple of seconds, you can quickly 
> see the threads accumulating in this state.
> 
> What we don't know:
> 
> - why is the pool getting full?
> - why is this situation persistent, i.e. it seems no more connections 
> are freed.
> 
> The seconds point is the important one. I don't have a good explanation 
> here, and checking with the commons mailing lists might be a good idea.
> 
> Of course a lot of dbcp users hang around on this list here. To get some 
> feedback from them, maybe start a new thread with a more specific Subject.
> 
>> In the STDOUT logs of the past few days, there are no messages at all
>> saying
>> something like 'DBCP object created'. Shouldn't there be such messages
>> already?
> 
> Yes, if you had logAbandoned="true" during that time, and dbcp detected 
> any connections, which were not freed. Again: I have no convincing 
> hypothesis what's happening, apart from the fact, that the solution lies 
> in the subsytems webapp/DBCP/database.
> 
>> And finally, would you advise me to install the 1.2.26 version of the
>> isapi_redirector connector again? As well as the 1.1.12 (or 1.1.13, but I
>> can't find it for Win64) version of the APR?
> 
> 1.2.26: first solve your db pool problem, at least until the situation 
> gets stable. Updating to 1.2.26 is optimization and not critical. 
> Concentrate on the pool first.
> 
> The same for tcnative 1.1.13 or the forthcoming 1.1.14 (I guess that 
> will be announced soon).
> 
>> Thanks. Jesse.
> 
> Regards,
> 
> Rainer
> 
>> Rainer Jung-3 wrote:
>>> So maybe start with something like
>>>
>>> initialSize="10"
>>> maxActive="50"
>>> maxIdle"10"
>>> minIdle="0"
>>> maxWait="5000" 	
>>>
>>> and check via netstat, how many connections you actually use during peak 
>>> load. Make sure, your database is correctly configured to handle the 
>>> maxActive connections.
>>>
> 
> 
> -- 
> kippdata
> informationstechnologie GmbH   Tel: 0228 98549 -0
> Bornheimer Str. 33a            Fax: 0228 98549 -50
> 53111 Bonn                     www.kippdata.de
> 
> HRB 8018 Amtsgericht Bonn / USt.-IdNr. DE 196 457 417
> Geschäftsführer: Dr. Thomas Höfer, Rainer Jung, Sven Maurmann
> ===============================
> kippdata
> informationstechnologie GmbH   Tel: +49 228 98549 -0
> Bornheimer Str. 33a            Fax: +49 228 98549 -50
> D-53111 Bonn                   www.kippdata.de
> 
> HRB 8018 Amtsgericht Bonn / USt.-IdNr. DE 196 457 417
> Geschäftsführer: Dr. Thomas Höfer, Rainer Jung, Sven Maurmann
> 
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