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Oracle 12.2 AIX 7.2 - sudden increase of cluster traffic - gc cr multi block mixed

user591200
user591200 Member Posts: 42 Bronze Badge
edited Sep 22, 2020 3:38AM in Real Application Clusters

Hi ,

I am observing cluster traffic been increased with the wait event -  gc cr multi block mixed

DatabaseSnapshot IdsNumber of InstancesNumber of HostsReport Total (minutes)
IdNameUnique NameRoleEditionRACCDBBlock SizeBeginEndIn ReportTotalIn ReportTotalDB timeElapsed time
4111447627ABCABCPRIMARYEEYESYES819252438524403333576.5230.26

Top ADDM Findings by Average Active Sessions

Finding NameAvg active sessions of the taskPercent active sessions of findingTask NameBegin Snap TimeEnd Snap Time
Top SQL Statements18.8794.76ADDM:4111447627_5243928-Jul-20 16:0028-Jul-20 16:15
Top SQL Statements19.2291.52ADDM:4111447627_5244028-Jul-20 16:1528-Jul-20 16:30
Global Cache Messaging19.2251.05ADDM:4111447627_5244028-Jul-20 16:1528-Jul-20 16:30
Global Cache Messaging18.8747.64ADDM:4111447627_5243928-Jul-20 16:0028-Jul-20 16:15
Top Segments by "User I/O" and "Cluster"19.2231.99ADDM:4111447627_5244028-Jul-20 16:1528-Jul-20 16:30

Top Timed Events

  • Instance '*' - cluster wide summary
  •   '*' Waits, %Timeouts, Wait Time Total(s) : Cluster-wide total for the wait event
  •   '*' 'Wait Time Avg' : Cluster-wide average computed as (Wait Time Total / Event Waits)
  •   '*' Summary 'Avg Wait Time ' : Per-instance 'Wait Time Avg ' used to compute the following statistics
  •   '*' [Avg/Min/Max/Std Dev] : average/minimum/maximum/standard deviation of per-instance 'Wait Time Avg'
  •   '*' Cnt : count of instances with wait times for the event

I#ClassEventWaits%TimeoutsTotal(s)Avg Wait%DB timeAvgMinMaxStd DevCnt
*Clustergc cr multi block mixed1,986,3240.008,547.994.30ms24.714.30ms4.24ms4.34ms59.69us3

  *

DB CPU6,315.5318.263

  *

User I/Odb file sequential read4,538,4810.003,946.50869.56us11.41868.29us804.89us926.18us60.83us3

  *

User I/Odb file parallel read1,864,9810.003,048.701.63ms8.811.63ms1.40ms1.89ms243.33us3

  *

Clustergc cr grant 2-way2,686,9260.002,662.63.99ms7.70.99ms.97ms1.01ms21.49us3

  *

Clustergc cr multi block grant439,4030.001,350.703.07ms3.903.07ms3.06ms3.09ms16.65us3

  *

Clustergc cr grant congested286,9150.001,076.503.75ms3.113.75ms3.63ms3.84ms105.31us3

  *

Clustergc current block 2-way1,026,4510.00942.21917.93us2.72918.19us889.68us935.78us24.92us3

  *

Clustergc current block congested176,1700.00766.814.35ms2.224.35ms4.18ms4.48ms155.89us3

  *

Clustergc current block 3-way372,3250.00740.181.99ms2.141.99ms1.94ms2.02ms39.57us3
1Clustergc cr multi block mixed676,2920.002,864.574.24ms24.06

  1

DB CPU2,124.4817.85

  1

User I/Odb file sequential read1,567,0410.001,451.36926.18us12.19

  1

User I/Odb file parallel read638,2470.001,205.101.89ms10.12

  1

Clustergc cr grant 2-way934,7380.00904.04.97ms7.59

  1

Clustergc cr multi block grant150,4730.00461.803.07ms3.88

  1

Clustergc cr grant congested92,4760.00336.043.63ms2.82

  1

Clustergc current block 2-way349,5140.00310.95889.68us2.61

  1

Clustergc current block 3-way127,9790.00248.751.94ms2.09

  1

Clustergc current block congested54,8540.00229.124.18ms1.92
2Clustergc cr multi block mixed663,8350.002,875.724.33ms24.73

  2

DB CPU2,092.0517.99

  2

User I/Odb file sequential read1,501,3180.001,311.85873.80us11.28

  2

User I/Odb file parallel read620,0630.00991.501.60ms8.53

  2

Clustergc cr grant 2-way881,7680.00888.741.01ms7.64

  2

Clustergc cr multi block grant143,8550.00444.893.09ms3.83

  2

Clustergc cr grant congested94,4560.00356.563.77ms3.07

  2

Clustergc current block 2-way345,1400.00322.98935.78us2.78

  2

Clustergc current block congested58,8310.00257.504.38ms2.21

  2

Clustergc current block 3-way124,2590.00249.142.00ms2.14
3Clustergc cr multi block mixed646,1970.002,807.704.34ms25.39

  3

DB CPU2,099.0018.98

  3

User I/Odb file sequential read1,470,1220.001,183.29804.89us10.70

  3

Clustergc cr grant 2-way870,4200.00869.851.00ms7.87

  3

User I/Odb file parallel read606,6710.00852.101.40ms7.71

  3

Clustergc cr multi block grant145,0750.00444.013.06ms4.02

  3

Clustergc cr grant congested99,9830.00383.913.84ms3.47

  3

Clustergc current block 2-way331,7970.00308.28929.11us2.79

  3

Clustergc current block congested62,4850.00280.194.48ms2.53

  3

Clustergc current block 3-way120,0870.00242.292.02ms2.19

Top Timed Foreground Events

  • Foreground Activity is captured in release 11g and above
  • For prior releases, Foreground Activity is computed as difference between Total Activty and Background Activity
  • Instance '*' - cluster wide summary
  •   '*' Waits, %Timeouts, Wait Time Total(s) : Cluster-wide total for the wait event
  •   '*' 'Wait Time Avg' : Cluster-wide average computed as (Wait Time Total / Event Waits)
  •   '*' Summary 'Avg Wait Time' : Per-instance 'Wait Time Avg' used to compute the following statistics
  •   '*' [Avg/Min/Max/Std Dev] : average/minimum/maximum/standard deviation of per-instance 'Wait Time Avg'
  •   '*' Cnt : count of instances with wait times for the event
<td align="right" class="awrc" headers="WaitTim
WaitEventWait TimeSummary Avg Wait Time
I#ClassEventWaits%TimeoutsTotal(s)Avg Wait%DB timeAvgMinMaxStd DevCnt
*Clustergc cr multi block mixed1,985,4290.008,546.114.30ms24.714.31ms4.24ms4.35ms59.91us3

  *

DB CPU6,315.5318.263

  *

User I/Odb file sequential read4,529,9440.003,939.57869.67us11.39868.40us805.12us926.36us60.79us3

  *

User I/Odb file parallel read1,864,9660.003,048.681.63ms8.811.63ms1.40ms1.89ms243.34us3

  *

Clustergc cr grant 2-way2,685,3510.002,661.43.99ms7.69.99ms.97ms1.01ms21.43us3

  *

Clustergc cr multi block grant439,0770.001,349.743.07ms3.903.07ms3.06ms3.09ms16.07us3

  *

Clustergc cr grant congested286,7800.001,076.083.75ms3.113.75ms3.63ms3.84ms105.09us3

  *

Clustergc current block 2-way1,022,4580.00938.85918.22us2.71918.50us889.73us936.15us25.13us3

  *

Clustergc current block congested175,6440.00764.564.35ms2.214.35ms4.18ms4.49ms157.41us3

  *

Clustergc current block 3-way371,4770.00738.561.99ms2.141.99ms1.94ms2.02ms40.67us3
1Clustergc cr multi block mixed676,0000.002,863.854.24ms24.06

  1

DB CPU2,124.4817.85

  1

User I/Odb file sequential read1,563,5570.001,448.42926.36us12.17

  1

User I/Odb file parallel read638,2400.001,205.091.89ms10.12

  1

Clustergc cr grant 2-way933,9360.00903.45.97ms7.59

  1

Clustergc cr multi block grant150,3910.00461.553.07ms3.88

  1

Clustergc cr grant congested92,4080.00335.843.63ms2.82

  1

Clustergc current block 2-way348,3790.00309.96889.73us2.60

  1

Clustergc current block 3-way127,7700.00248.201.94ms2.08

  1

Clustergc current block congested54,6870.00228.344.18ms1.92
2Clustergc cr multi block mixed663,5960.002,875.334.33ms24.73

  2

DB CPU2,092.0517.99

  2

User I/Odb file sequential read1,499,7040.001,310.29873.70us11.27

  2

User I/Odb file parallel read620,0600.00991.501.60ms8.53

  2

Clustergc cr grant 2-way881,4360.00888.481.01ms

Answers