Re: Global Cache and Enqueue Services statistics
Date: Mon, 30 Jul 2012 13:34:24 -0700 (PDT)
Message-ID: <1343680464.878.YahooMailNeo_at_web83607.mail.sp1.yahoo.com>
Hi Amir,
What are your "Top 5 Wait Events" in the AWR during your load tests? The GC and ES statistics themselves don't mean much (except that you have very high Avg. Message Sent Queue Time) unless we know what is the source of your DB's pain point. Let's start our discussion with the "Top 5 Waits" and then then the Top SQL that relates to it.
Cheers,
Gaja
Gaja Krishna Vaidyanatha,
CEO & Founder, DBPerfMan LLC
http://www.dbperfman.com
http://www.dbcloudman.com
Phone - +1-650-743-6060
LinkedIn - http://www.linkedin.com/in/gajakrishnavaidyanatha
Co-author: Oracle Insights:Tales of the Oak Table - http://www.apress.com/9781590593875 Primary Author: Oracle Performance Tuning 101 - http://www.amzn.com/0072131454 Enabling Cloud Deployment & Management for Oracle Databases
From: "Hameed, Amir" <Amir.Hameed_at_xerox.com> To: oracle-l_at_freelists.org
Sent: Monday, July 30, 2012 1:15 PM
Subject: Global Cache and Enqueue Services statistics
Folks,
I have a three-node Oracle RAC environment running on Solaris 10. The
Grid and DB versions are 11.2.0.3 and 11.1.0.7 respectively. We ran a
load test against the environment to simulate our load in production.
The transaction timings were off when compared to timings from the
single instance of the same environment. When I look at AWR from all
instances, the following workload statistics seem a bit high:
Avg message sent queue time
Avg global cache current block receive time (ms)
Avg global cache cr block flush time
The CPU utilization was over 90% idle on each RAC node during the test. The interconnect is an aggregated link of two 10GbE NIC. Database files are on RAID-5 SSDs where as redo logs are on dedicated RAID-10 SAS drives. Is there anything that I should look at closely that could help identify reason for higher timings for these statistics? Also, what is considered as good timing for these statistics?
Thank you,
Amir
Instance #1
Global Cache and Enqueue Services - Workload Characteristics
Avg global enqueue get time (ms): 1.4
Avg global cache cr block receive time (ms): 3.7
Avg global cache current block receive time (ms): 13.0
Avg global cache cr block build time (ms): 0.0
Avg global cache cr block send time (ms): 0.0
Global cache log flushes for cr blocks served %: 8.0
Avg global cache cr block flush time (ms): 7.5
Avg global cache current block pin time (ms): 6.2
Avg global cache current block send time (ms): 0.3
Global cache log flushes for current blocks served %: 13.4
Avg global cache current block flush time (ms): 5.1
Global Cache and Enqueue Services - Messaging Statistics
Avg message sent queue time (ms): 7736.8
Instance #2
Global Cache and Enqueue Services - Workload Characteristics
Avg global enqueue get time (ms): 0.8
Avg global cache cr block receive time (ms): 2.2
Avg global cache current block receive time (ms): 11.2
Avg global cache cr block build time (ms): 0.0
Avg global cache cr block send time (ms): 0.0
Global cache log flushes for cr blocks served %: 6.8
Avg global cache cr block flush time (ms): 12.0
Avg global cache current block pin time (ms): 10.5
Avg global cache current block send time (ms): 0.3
Global cache log flushes for current blocks served %: 15.0
Avg global cache current block flush time (ms): 6.4
Global Cache and Enqueue Services - Messaging Statistics
Avg message sent queue time (ms): 9120.8
Instance #3
Global Cache and Enqueue Services - Workload Characteristics
Avg global enqueue get time (ms): 0.6
Avg global cache cr block receive time (ms): 2.9
Avg global cache current block receive time (ms): 10.4
Avg global cache cr block build time (ms): 0.0
Avg global cache cr block send time (ms): 0.0
Global cache log flushes for cr blocks served %: 7.1
Avg global cache cr block flush time (ms): 9.6
Avg global cache current block pin time (ms): 14.3
Avg global cache current block send time (ms): 0.3
Global cache log flushes for current blocks served %: 14.5
Avg global cache current block flush time (ms): 6.5
Global Cache and Enqueue Services - Messaging Statistics
Avg message sent queue time (ms): 8390.3
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