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High Library Cache Lock and Library Cache Load Lock Waits During Concurrent Heavy Mixed PMOPs and DML on Several Partitioned Tables (Doc ID 2181034.1)

Last updated on APRIL 08, 2020

Applies to:

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


High "library cache lock" with "library cache load lock" waits were seen when there were parallel maintenance operations (PMOPs) with concurrent DML on the same table.  In this case, for the same table, a new partition was added and a different one dropped about every second while DML was also occurring.   This same type of workload was being done on other partitioned tables at the same time. 

An AWR might look something like the following:



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