Hello Patrick,
 
> i have sapdb 7.3.24 running on red hat 7.2. let's call this 
> machine db.
> on a second red hat 7.2 machine i have jboss 2.4.4 running. let's call
> this machine web.
> 
> ok, jboss running on web connects to the database running on db. the
> network connection between both machines is fast enough (connected
> through 2 extra ethernet adapters which only handle this connection).
> 
> the whole thing runs quite stable, except we have heavy load on jboss
> (and thus on the database). on heavy load, jboss prints a lot of
> 
> "[11:23:10,310,TxCapsule] Transaction XidImpl [FormatId=257,
> GlobalId=web//44389, BranchQual=] timed out. status=STATUS_ACTIVE"
> 
> messages into its log and after some minute jboss cannot recieve any
> data from the database anymore. a restart of jboss solves the problem,
> everything works fine after that.

As a restart of JBoss (not SAP DB) solves that, I fear there is some
deadlocking that blocks some transactions, leading to blocked connections
that are not in the connection pool, finally leading to blocking 
everything.

The (extended) DB parameter REQUEST_TIMEOUT tells about the time the database
waits until waiting for a lock is given up, and an error is given to 
the client (JBoss). The default of 5000 seconds (more than 1 hour) is 
probably more than the patience JBoss' its own transaction manager has.
I fear it then locks up itself somehow when trying to free the connection
and give it back to the pool, as the deadlocked statement may not have 
be canceled by JBoss successfully.

So, it may be (aside from making some deadlock analysis) a good idea to
limit REQUEST_TIMEOUT (try the minimum, 30 seconds), and try again. 

You may possibly also need to adjust some parameter in JBoss that manages
the transaction timeout to match the database setting, but I cannot say how 
to do this - consult a JBoss expert :-)

Regards
Alexander Schr�der
SAP DB, SAP Labs Berlin

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