Re: Instance gets down after approx 500 hits; Database backup; Connection pooling with Single Database Context
Re: Instance gets down after approx 500 hits; Database backup; Connection pooling with Single Database Context
- Subject: Re: Instance gets down after approx 500 hits; Database backup; Connection pooling with Single Database Context
- From: Chuck Hill <email@hidden>
- Date: Fri, 23 Apr 2010 11:06:11 -0700
Hi Daniel,
On Apr 23, 2010, at 10:59 AM, Daniel Roy wrote:
Hi,
I work with Farrukh :)
The application was indeed not responding as I recall.
Which is odd, as it did not seem to be doing anything at all. Perhaps
the app gets slow, the woadaptor gives up on it and marks it as dead
and sends no more requests. The app then recovers and is idle,
though effectively dead.
Also, we do dispatch requests concurrently
(WOAllowsConcurrentRequestHandling=true). I wonder if enabling
ERXStatisticsStore would give us some useful information....
It might. It should indicate if requests start taking longer to
process. You could also enable WO logging (see WO's apache.conf) to
see what the woadaptor has to say.
Chuck
Daniel Roy
email@hidden
Software Developer
On 2010-04-23, at 12:05 PM, Chuck Hill wrote:
On Apr 23, 2010, at 12:29 AM, Farrukh Ijaz wrote:
Thanks Chuck for your response.
On 2010-04-23, at 1:09 AM, Chuck Hill wrote:
On Apr 22, 2010, at 2:17 PM, Farrukh Ijaz wrote:
Hi WOGurus,
1. We've few applications based on same database structure. What
happens, one of the application after approximately 500 hits
gets down. What can be the reason for that? (I know the question
is too broad but would appreciate for any clues).
What does "gets down" mean? Runs out of memory? The JVM process
crashes? Deadlocks?
No, memory is not the issue. Instances stop responding and we need
to use JavaMonitor to stop/start the instance or sometimes when
JavaMonitor can't perform the operation need to kill the java
process. Attached is the stack trace.
<stack.txt>
I don't see any dead locks there. Was that application not
responding when you captured that? Are you dispatching requests
concurrently?
2. Sometimes the logs show message with Runtime Exception
"Statement running too long" what can be the reason.
The statement running too long? Un-optimized or sub-optimal SQL
can cause this. Which database? Using Wonder?
I'm sure there are indexes. Can you explain "sub-optimal SQL" in
this context? We use PostgreSQL and completely dependent on Wonder
extensions.
Different databases optimize SQL differently. Things like sub-
selects vs joins, ANDs vs one IN can make a big difference on some
databases.
Chuck
--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their
overall knowledge of WebObjects or who are trying to solve specific
problems.
http://www.global-village.net/products/practical_webobjects
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