RE: Lot of Latch Free and Enqueue Hash Chain Wait Events

I would start with reviewing whether your resource manager definitions are needed (the fastest way to do anything is to not do it at all) and whether or not your CPU is reported to Oracle and the OS as oversubscribed (which is probably wait states in the CPU itself shoving memory in and out, but that is another story).  

Also see whether the total time of these waits amounts to actual delays to things that are important to you that they be fast. You can read up on that notion at Method-R, but the short answer is that if the time of these latch free waits (as opposed to waiting for “Yes, you may run on the CPU, sez I the resmgr!”) is very small or even is large but doesn’t affect the jobs in your priority resource groups (if you have any), then you don’t care.  

mwf  

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Ravi Teja Bellamkonda Sent: Tuesday, October 03, 2017 10:38 AM To: oracle-l
Subject: RE: Lot of Latch Free and Enqueue Hash Chain Wait Events  

Hi List,  

First of all, thank you for all the time and support.  

Problem Statement is that under load we are observing a lot of Latch Free wait events which are followed by Enqueue Hash Chains.  

Inline image 2  

Digging a bit more I was able to find the latch.  

Inline image 1  

I cannot make any conclusions based on this. Please provide any recommendations on solving this issue or conclusions for this event.

-- 

Thanks & Regards,

Ravi Teja Bellamkonda

 













--
http://www.freelists.org/webpage/oracle-l





image/png attachment: image001.png



image/png attachment: image002.png