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12c RAC DDL Performance Issue: High "enq: IV - contention" etc if CPU Count is Different (Doc ID 2028503.1)

Last updated on FEBRUARY 14, 2019

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 12.1]
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Information in this document applies to any platform.


12c RAC database seeing high "enq: IV - contention":

From awr report:

Top 10 Foreground Events by Total Wait Time
Event Waits Total Wait Time (sec) Wait Avg(ms) % DB time Wait Class
enq: IV - contention 52,914 1688.4 31.91 42.8 Other
row cache lock 44,865 896.8 19.99 22.7 Concurrency


tkprof of 10046 trace of SQL statement shows the same event in the top:

Event waited on Times Max. Wait Total Waited
---------------------------------------- Waited ---------- ------------
enq: IV - contention 6017 0.32 287.68
row cache lock 957 0.20 7.48
library cache lock 631 0.13 15.10
library cache pin 616 0.11 14.54




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