RE: Slow Checkpointing....



>>  I don’t *believe* adding writers should 
help unless the existing
writers are already pegged. Since it completes when you checkpoint the 
hours
versus minutes part does not add up.
Thanks Mark. Oracle support hasn't provided any information on why we need to 
add more dbwr processes. System load is not high and certainly the dbwr 
processes aren't pegging CPUs.

-Upendra



From: mwf@xxxxxxxx
To: nupendra@xxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
Subject: RE: Slow Checkpointing....
Date: Tue, 29 Jun 2010 14:59:44 -0400



















Are the two writer processes you already
have pegged on CPU? Has anyone monkeyed around with renice on other processes so
the db writers only get time when you checkpoint?

 

I don’t *believe* adding writers should help unless the existing
writers are already pegged. Since it completes when you checkpoint the hours
versus minutes part does not add up.

 

good luck,

 

mwf









From:
oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf 
Of Upendra N

Sent: Tuesday, June 29, 2010 2:48
PM

To: oracle-l@xxxxxxxxxxxxx

Subject: Slow Checkpointing....



 

I have a 11.1.0.7 EE database
running on Solaris 10 using ZFS storage volumes. 

We have two ZFS pools - 1. control files and redo logs, 2. Data files.



We have been seeing issues where the redo logs stay in "active"
status for a long period (several hours - even when the system is idle). We are
able to manually checkpoint without any errors, it completes <5 mins.

Oracle support is suggesting to increase dbwr processes.

We have 8 CPU (single core) sockets with db_writer_processes =2.

Have anyone seen similar issues?  What do you think?



Thanks much 

-Upendra













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