Row cache lock wait issue in RAC

From: Luca Canali <Luca.Canali_at_cern.ch>
Date: Wed, 31 May 2006 22:23:50 +0200
Message-ID: <F9411E3A291FB5449991ED7E624D27F4D19418@cernxchg20.cern.ch>

I am stress testing an application that performs massive inserts (logs tons of data) into Oracle tables using direct path insert. Multiple tables are used to provide scalability (each log source inserts into a dedicated table). This application uses direct path inserts and bypasses the cache so I can see that it also scales in RAC (10g RAC, 6 nodes).

BUT increasing the number of log sources I have now started to see the following bottleneck: row cache wait (on dc_tablespace_quotas), for example from a 10046 trace:

---

WAIT #19: nam='row cache lock' ela= 2888862 cache id=5 mode=0 request=5 obj#=76647 tim=1122164147766228
WAIT #19: nam='row cache lock' ela= 2824967 cache id=5 mode=0 request=5 obj#=76647 tim=1122164150591291

It looks to me as row cache lock contention between direct path inserts, probably made worse by rac/GES. (Note also that I don't enforce tablespace quotas (the application owner has unlimited tablespace).

Any ideas on how to tune this?

Thanks,
Luca

--

http://www.freelists.org/webpage/oracle-l Received on Wed May 31 2006 - 15:23:50 CDT