Re: Global Cache and Enqueue Services statistics
- From: "Tim Gorman" <tim@xxxxxxxxx>
- To: Amir.Hameed@xxxxxxxxx, oracle-l@xxxxxxxxxxxxx
- Date: Mon, 30 Jul 2012 20:39:25 +0000
Amir,
In a head-to-head comparison of the same workload on similar servers, non-RAC
will outperform RAC due to the additional waits introduced by GC and GES,
because each I/O and enqueue operation now has to perform additional GC and GES
services to maintain cache- and enqueue-coherency across the cluster. In short,
waits on Global Cache and Global Enqueue events are exactly what was purchased
with RAC.
Perhaps validate the new hardware and storage by re-running the same load test
from just one of the three instances started with CLUSTER_DATABASEúLSE?
Hope this helps...
Thanks!
Tim Gorman
consultant => Evergreen Database Technologies, Inc.
postal => PO Box 352151, Westminster CO 80035
email => Tim@xxxxxxxxx
mobile => +1-303-885-4526
fax => +1-303-484-3608
Lost Data? => http://www.ora600.be/ for info about DUDE...
-----Original Message-----
From: Hameed, Amir [mailto:Amir.Hameed@xxxxxxxxx]
Sent: Monday, July 30, 2012 02:15 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Global Cache and Enqueue Services statistics
Folks,I have a three-node Oracle RAC environment running on Solaris 10. TheGrid
and DB versions are 11.2.0.3 and 11.1.0.7 respectively. We ran aload test
against the environment to simulate our load in production.The transaction
timings were off when compared to timings from thesingle instance of the same
environment. When I look at AWR from allinstances, the following workload
statistics seem a bit high: Avg message sent queue timeAvg 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 filesare on RAID-5 SSDs where as
redo logs are on dedicated RAID-10 SASdrives. Is there anything that I should
look at closely that could helpidentify reason for higher timings for these
statistics? Also, what isconsidered 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): 0.3Global 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): 0.3Global 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): 0.3Global 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 --//www.freelists.org/webpage/oracle-l
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