Re: Global Cache and Enqueue Services statistics

  • From: Gaja Krishna Vaidyanatha <gajav@xxxxxxxxx>
  • To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
  • Date: Mon, 30 Jul 2012 13:34:24 -0700 (PDT)

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@xxxxxxxxx>
To: oracle-l@xxxxxxxxxxxxx 
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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