Re: Row cache lock wait issue in RAC


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?

Just an idea: why don't you try to remove user's unlimited quota privilege and assign a specific quota?


Regards
Dimitre 

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