Re: Using RDBMS Have You Experienced Enq: Hwm - Contention?

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Date: Wed, 6 Apr 2011 09:10:29 +0300
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our solution was a patch for 6376915 (for oracle version 10204) It helped.

After that another LOB event (sorry, I've forgot the details) poped-out but for that we knew what to do - LOB cache helped (thanks to small LOB size.)

Brgds, Laimis N

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  From:       fmhabash <>                                                                                                     
  To:         Oracle L <>                                                                                                 
  Date:       2011.04.05 22:52                                                                                                                  
  Subject:    Using RDBMS Have You Experienced Enq: Hwm - Contention?                                                                 

We go hit by this event recently and would like validate the scenario and the proposed solutions against your experience if you encountered it. This event affected a LOB segment in an ASSM tablespaces in a RAC database.
This is what I have found so far ...
1) As temporary workaround, manually add extra space to the LOB segment. 2) Bug 6376915 (affecting

  • >= EVENT="44951 TRACE NAME CONTEXT FOREVER, LEVEL < 1 - 1024 >"
  • set PCTVERSION to 100: but never able to use blocks freed by updated blobs 3) Bug 6413373 (LOB in RAC and ASSM) - Lob HW enqueue contention: LOBs in ASSM tablespaces
  • Set FREEPOOLS is set to a value >= the number of instances
  • Partition the table into a number of partitions sufficient 4) Try alter system set"_insert_enable_hwm_brokered"=false

If you did encounter this issue, what was you rca and final resolution?

Thank you.


Received on Wed Apr 06 2011 - 01:10:29 CDT

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