enq: HW - contention
Short Description
Enqueue wait. Segment High Water mark contention during concurrent inserts
Additional Information​
An enqueue is a wait for a resource held by another.
The enq: HW - contention is seen when a multiple sessions attempt to move the segment High Water Mark concurrently. This can be multiple independent sessions or a parallel insert.
How to reduce this wait​
Consider increasing freelists or moving segments to ASSM.
Consider adjusting the parallelism of the insert.
Additional Links​
Oracle docs - Oracle Enqueue Names
Vineet Arya - enq: HW - contention- High Water Mark Brokered
Burleson - enq: HW contention tips
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