[Mulgara-dev] 2.1.6, SOAP, Autocommit and Transactions

[David Smith]

Gentlemen,

I'm trying to track down a change in behavior that snuck up on me.

Problem:	
ITQL inserts/delete hanging (or not returning for a really long time).

Situation:
Using Mulgara 2.1.4 in production, duplicated problem with 2.1.6
Using SOAP (I know).

>>> What is the expected behavior for transactions, exceptions and
timeouts in SOAP calls? <<<

In general, when I need to perform updates (delete, insert) it will be
within a single SOAP call, surrounded by  AutoCommit OFF, ON statements.
I need to know when the update fails, and how to recover.

Further Description
There's been a change in behavior (not sure when it started), 
in that what used to happen if a second (or third, etc) thread attempted
to perform an operation while a first thread holds the writelock
(autocommit off), 
is that an exception would be thrown (usually indicating
MulgaraTransactionException).

In the past I was able to dig through the exception text and know
whether I needed to rollback or simply retry the operation.

What I am currently seeing that that the second thread (SOAP call)
hangs, and does not return.

If I artificially shorten the <TransactionTimeout> in conf file, I can
get an error like:

=========
javax.xml.soap.SOAPException: ItqlInterpreter error - Query failed:
transaction-timeout
Caused by: (MulgaraTransactionException) Attempt to activate failed
transaction
Caused by: (MulgaraTransactionException) transaction-timeout
=========

I need to help tracking down this issue.


Other puzzles:

I don't know how this relates, but I have also seen (occasionally) the
following log entries:

2010-01-11 16:21:23,761 [RMI TCP Connection(108)-10.3.3.51] -
org.mulgara.resolver.MulgaraTransactionFactory - Terminating session
while holding writelock:org.mulgara.resolver.DatabaseSession at 2ee02595:
org.mulgara.resolver.MulgaraInternalTransaction at 1c1150fb
2010-01-11 16:21:23,793 [btpool0-13 -
/webservices/services/ItqlBeanService] -
org.mulgara.itql.ItqlInterpreterBean - Execute query failed.  Returning
error
java.lang.ClassCastException: org.mulgara.query.operation.Deletion
cannot be cast to org.mulgara.query.operation.TxOp
	at
org.mulgara.itql.TqlAutoInterpreter.updateConnectionsForTx(TqlAutoInterp
reter.java:362)
	at
org.mulgara.itql.TqlAutoInterpreter.executeCommand(TqlAutoInterpreter.ja
va:118)
	at
org.mulgara.itql.ItqlInterpreterBean.executeCommand(ItqlInterpreterBean.
java:1156)
	at
org.mulgara.itql.ItqlInterpreterBean.execute(ItqlInterpreterBean.java:36
0)
	at
org.mulgara.itql.ItqlInterpreterBean.executeQueryToString(ItqlInterprete
rBean.java:419)
.
.
.
2010-01-11 16:21:23,793 [btpool0-13 -
/webservices/services/ItqlBeanService] -
org.mulgara.itql.ItqlInterpreterBean - Failed to execute query
javax.xml.soap.SOAPException: ItqlInterpreter error -
org.mulgara.query.operation.Deletion cannot be cast to
org.mulgara.query.operation.TxOp
	at
org.mulgara.itql.ItqlInterpreterBean.execute(ItqlInterpreterBean.java:38
2)
	at
org.mulgara.itql.ItqlInterpreterBean.executeQueryToString(ItqlInterprete
rBean.java:419)
	at sun.reflect.GeneratedMethodAccessor16.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown
Source)




Thanks

Dave Smith
Viewpoint





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