[Mondrian] problems with concurrency (shepherd) execution

Luc Boudreau lucboudreau at gmail.com
Tue Oct 18 12:01:42 EDT 2011


Paul,

I've reproduced your issue and fixed it on our side. Seems like the
Saiku code is executing the same OlapStatement twice concurrently (or
the olap4j CellSet). I added a check in our code that cancels the
previous execution prior to running it again, but you might want to
look into your server code and make sure that you do not share
statements across your HTTP threads.

Luc


On Tue, Oct 18, 2011 at 5:32 AM, Paul Stoellberger
<p.stoellberger at gmail.com> wrote:
> I filed it as http://jira.pentaho.com/browse/MONDRIAN-1014
> Is the monitoring refactoring part of 3.3?
> -Paul
> On Oct 18, 2011, at 9:02 AM, Julian Hyde wrote:
>
> On Oct 17, 2011, at 6:01 AM, Paul Stoellberger wrote:
>
> Hi,
> some users have report the below pasted bug when using saiku (mondrian
> 3.3-SNAPSHOT). it doesn't always appear, just sometimes.... and in some
> environments... i couldnt find a clear path to reproduce the problem...
>
> I think I've seen a similar problem -- so even though it's not consistently
> reproducible, I'm sure there's a bug here. Can you log it please.
> I might have fixed it in my current set of changes for monitoring. (I had to
> do quite a bit of work on connection/statement/execution lifecycle.) But
> it's still good to have it logged.
>
> My assumption is, since statement.end() is called in RolapConnection:642
> (see stacktrace) that in case of an error StatementImpl throws an error
> because the execution hasn't finished
> What confuses me as well in MondrianOlap4jStatement is that this.execution
> is never set. only in start() and in there i cant see how that would ever
> work by just using that
>
> I think start() is OK. It first ensures that the statement is not already
> executing, then marks it as executing by setting the 'execution' field.
> But I can't think what might be cause right now.
> Julian
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