OBIEE with OLAP Concurrency

[Matthew Turner]

Good Morning,

I've recently implemented OBIEE 11g with OLAP and I'm now going through a performance testing phase - specifically looking at concurrency issues.

OBIEE 11g OLAP is now implemented by passing OLAP specific string to a system function OLAP_TABLE which returns the result set.

The test I carried out was to run the same SQL that OBIEE generated 3 times concurrently from SQL*Plus, whilst tracing the results (10046, level 12).

The first query returned in around 20 seconds with the significant wait event being the fetch as normal.

The 2nd query introduced a new wait event cursor Pin S wait on X which added an extra 4.5 seconds of elapsed time. (In addition further 7 seconds unaccounted for time which I'm investigating).

The 3rd query cursor Pin S wait on X increased to 10 seconds.

The new wait event cursor Pin S wait on X  I believe to be a library cache event, as a latch has been taken out by query 1 during its hard parse process which then gets taken out by query 2 etc...

It appears to me that OLAP_TABLE has introduced a bottleneck, and is forcing each session in turn to queue to take out the latch for the hard parse.

Questions:

Has anybody else implemented OBIEE with OLAP in a large multi-user environment with lots of concurrent users?

Has anybody else experienced library latch issues with OLAP_TABLE?

Thanks in advance,

Matt