concurrency waits after partitioning with SPB

  • From: "Walker, Jed S" <Jed_Walker@xxxxxxxxxxxxxxxxx>
  • To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 23 Oct 2012 06:41:02 +0000

I'm writing this in the hope that someone has maybe seen this and found a 
solution. I also have an SR with Oracle.
RHEL5.6, oracle 11.2.0.3, 8-node RAC

Two RACS with one-direction Golden Gate replication. On the first I have 10 
live schemas, and on the second 2 live schemas. Both had 
optimizer_capture/use_sql_plan_baselines=true set due to instability in the 
past. I have an OLTP table that gets millions of inserts per day, and then is 
cleaned with a delete cleanup procedure. I have partitioned this table so I can 
do "drop partition" for cleanup instead (the delete cleanup often causes 
significant delay in replication, not to mention all the redo).

I partitioned on a small schema on the 2nd RAC with 2 schemas. I immediately 
began getting huge concurrency waits, specifically "cursor: pin s wait on x" on 
UPDATEs on this table. I did some research and turned off 
optimizer_use_sql_plan_baselines and the waits went away. I tried to turn this 
off on the first RAC hoping it was a simple fix, but the RAC didn't handle it 
well, so I turned it back on. I'm working with oracle and installed a patch for 
this particular issue, but it didn't work.

So, essentially, partitioning this table when optimizer_sql_plan_baselines = 
true results in these waits. Removing partitioning or setting 
optimizer_sql_plan_baselines = false resolves it. The main query is an UPDATE 
on the table, and SQL Tuning Advisor comes up with no suggestions.

Thanks,

Jed


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