We have three MOLAP cubes in our environment and lately with no
apparent changes to the Cubes or any other parameters, the cube
processing time has quadrupled. The server is shared by SQL server and
Analysis Services and with a processing time change from 5+ hrs to 20+
hrs, the cubes have become useless as it is time to reprocess them all
over again by the time the previoud run has completed.

I am not familiar with the internals of how the cubes work but know
that only one of them has gone berserk. Being a DBA, I reindexed the
cubes database, moved the processing folder to a different location to
avoid any disk issues, increased allocated processing memory, rebooted
the server, but with no improvement. Well, actually it was back to
normal for one day after the reboot and is now back to normal. To make
this even worse, we have the same scenario happening on the production
and reporting servers. The intention was to eventually shut down the
production runs once the validation that the migration to reporting was
good thru data validation.

Any suggestions are appreciated.
Thanks.

have you identified if the delay come from the reading step (reading from
the database to the cube) or the aggregation step?
does the volume of data has increased? have you recreated the aggregations
based on the new number of rows?

have you done a full process of the dimensions?
do you use a DCount measure?

sometimes the problem comes when the OLAP Server is not shutdown for a long
period and if you don't do a full process of the dimension.
but other cases can occurs

<ajampana (AT) gmail (DOT) com> wrote

Are these under heavying querying? What's your query log sample rate like?

We had a similar issue, our dimensions just got so big and we had too much
historical data. It eventually caught up.

Have you had a chance to run any perfmons on it? Try this one...

Analysys Server:Proc Aggs -> Temp file bytes written/sec

That number should stay at zero. If it's writing to disk then you'll
definitely see a performance loss. Also, make sure this temp folder is not
on the C drive.

What's the memory configuration like?





<ajampana (AT) gmail (DOT) com> wrote