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Former Member
May 06, 2015 at 03:39 PM

Performance and Tuning


I am currently running sp_iqemptyfile on large database and have run sp_iqsysmon. I have main cache (-iqmc) set at 96,000 or 96 GB on a solaris system with 125 GB of RAM.

I've run iqsysmon several times and I am getting back what looks like a high number for GDirty (Grabbed Dirty) --around 27857. The Performance and Tuning Guide indicates SWEEPER_THREADS_PERCENT or WASH_AREA_BUFFERS_PERCENT may need to be adjusted in such case.

Does anyone have any experience they can share with these two options?

Would I make the WASH_AREA_BUFFERS_PERCENT higher or lower to reduce the number of dirty reads?

Again, from sp_iqsysmon, I am also gettign a high number of IONumWaits (between 17 and 23 %) when the ideal is less than 10%. Performance and Tuning Guide indicates "Check for disk errors" or I/O retries. How would I check for I/O retries?

Also I have a high number of FalseMisses which may indicate rollbacks are occuring, according to Performance and Tuning manual. Any ideas on how to avoid this given the njumber should be 0 and I'm seeing 1.5 million total.

Thanks in advance for any commnets or suggestions.