[Mondrian] Re: Performance degradation

Matt Campbell mkambol at gmail.com
Tue Mar 3 17:25:10 EST 2009


I was able to reproduce this issue with a very simple Foodmart query.  The
following runs in under 2 seconds with changelist 10915.  It now takes
around 55 seconds with 12403.   From the little investigation I've done it
looks like most time is spent in executeStripe().
It's interesting, if I eliminate either part of the set the time drops back
down to ~2 seconds--i.e. eliminate either the GENERATE() or the
{Product.DEFAULTMEMBER, [Yearly Income].DEFAULTMEMBER}.  If they are
both present,
though, it takes 55 seconds.

SELECT            {GENERATE({[Product].[Product Name].MEMBERS},
             CROSSJOIN( {([Product].CURRENTMEMBER)},
           {[Yearly Income].[Yearly Income].MEMBERS}), ALL),
            {([Product].DEFAULTMEMBER,[Yearly Income].DEFAULTMEMBER)}
}
 ON AXIS(0)
FROM
            [Sales] ;


On Tue, Mar 3, 2009 at 11:03 AM, Matt Campbell <mkambol at gmail.com> wrote:

>
> During a run of a performance test we noticed a fairly significant increase
> in query time for queries involving very large numbers of cells.  We
> actually hadn't run this particular test in nearly a year, so the comparison
> is between changelist 10915 and 12403.
>
> The query is ridiculously large--nearly 200K tuples, intersected with 12
> measures.  With 10915 this query ran in a little over an hour.  With 12403
> it runs for over 5 hours.
>
> I haven't investigated much yet.  I'm going to create simple Foodmart query
> to try to reproduce, and then I'll try to narrow down where the bottleneck
> is.  I wanted to post, though, in case anyone has thoughts about this.
>
>
>
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