Bug 13930580 Workaround Effective

We put the workaround for Bug 13930580 in on Friday and the results have been much better than I expected.  Here is when the workaround went in as reported in the alert log:

Fri Jan 17 18:38:26 2014
ALTER SYSTEM SET _use_adaptive_log_file_sync='FALSE' SCOPE=BOTH;

Here are the log file sync average times.  Notice how they go down after 7 pm Friday:

END_INTERVAL_TIME          number of waits ave microseconds
-------------------------- --------------- ----------------
17-JAN-14 12.00.49.669 AM            78666       15432.6923
17-JAN-14 01.00.27.862 AM            13380       15509.9778
17-JAN-14 02.00.11.834 AM            15838       17254.2949
17-JAN-14 03.00.56.429 AM            10681       29832.4282
17-JAN-14 04.00.39.502 AM            26127       14880.2097
17-JAN-14 05.00.22.716 AM            21637       10952.5322
17-JAN-14 06.00.01.558 AM            67162       9756.44207
17-JAN-14 07.00.45.358 AM           123705       11755.6535
17-JAN-14 08.00.29.811 AM           223799       11341.2467
17-JAN-14 09.00.19.275 AM           319051       13651.4647
17-JAN-14 10.00.09.089 AM           507335       13991.5543
17-JAN-14 11.00.59.502 AM           583835       11609.8432
17-JAN-14 12.00.44.044 PM           627506       10857.4556
17-JAN-14 01.00.30.133 PM           610232       11233.9348
17-JAN-14 02.00.18.961 PM           664368       10880.3887
17-JAN-14 03.00.05.694 PM           647896       9865.96367
17-JAN-14 04.00.44.694 PM           538270       10425.6479
17-JAN-14 05.00.24.376 PM           343863       9873.98468
17-JAN-14 06.00.11.481 PM           169654       9735.80996
17-JAN-14 07.00.03.087 PM            87590       7046.92633
17-JAN-14 08.00.52.390 PM            69297       2904.62955
17-JAN-14 09.00.29.888 PM            38244       3017.15969
17-JAN-14 10.00.09.436 PM            28166       3876.77469
17-JAN-14 11.00.54.765 PM            23220       11109.3063
18-JAN-14 12.00.33.790 AM            13293       9749.99428
18-JAN-14 01.00.17.853 AM            15332       3797.76839
18-JAN-14 02.00.56.050 AM            16137       6167.15127
18-JAN-14 03.00.33.908 AM            14621       9664.63108
18-JAN-14 04.00.12.383 AM             9708        6024.9829
18-JAN-14 05.00.56.348 AM            14565       3618.76938
18-JAN-14 06.00.39.683 AM            14323       3517.45402
18-JAN-14 07.00.29.535 AM            38243       3753.46422
18-JAN-14 08.00.16.778 AM            44878       2280.22924
18-JAN-14 09.00.01.176 AM            73082       9689.52484
18-JAN-14 10.00.45.168 AM            99302       2094.03293
18-JAN-14 11.00.35.070 AM           148789       1898.40424
18-JAN-14 12.00.23.344 PM           151780       1932.64997
18-JAN-14 01.00.08.631 PM           186040       2183.18563
18-JAN-14 02.00.59.839 PM           199826       2328.87331
18-JAN-14 03.00.45.441 PM           210098        1335.9759
18-JAN-14 04.00.36.453 PM           177331       1448.39219
18-JAN-14 05.00.21.669 PM           150837       1375.07256
18-JAN-14 06.00.59.959 PM           122234       1228.21767
18-JAN-14 07.00.37.851 PM           116396       1334.64569
... skip a few to find some higher load times...
19-JAN-14 10.00.01.434 AM           557020       2131.02737
19-JAN-14 11.00.42.786 AM           700781       1621.16596
19-JAN-14 12.00.31.934 PM           715327       1671.72335
19-JAN-14 01.00.10.699 PM           718417       1553.98083
19-JAN-14 02.00.51.524 PM           730149        2466.6241
19-JAN-14 03.00.38.088 PM           628319       2465.45829

When the system is busy we are seeing less than 3000 microseconds = 3 milliseconds log file sync which is good.  We were seeing 10 milliseconds or more which isn’t that great.

Oracle support has been pushing this for a long time but our own testing wasn’t able to recreate the problem.  Have to hand it to them.  They were right!

Here is a link to my previous post on this issue: url

– Bobby

 

 

 

About Bobby

I live in Chandler, Arizona with my wife and three daughters. I work for US Foods, the second largest food distribution company in the United States. I've been working as an Oracle database administrator and PeopleSoft administrator since 1994. I'm very interested in Oracle performance tuning.
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