IF: Undo Wait Event - Enq: US - contention
(Doc ID 1951680.1)
Last updated on JANUARY 29, 2022
Applies to:
Oracle Database Cloud Schema Service - Version N/A and laterOracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup 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.
Symptoms
AWR reports shows enq: US - contention as the top or latch: row cache objects as top with enq: US - contention as one of the Top 5 wait events
Event Waits Time (s) (ms) Time Wait
------------------------------ ------------ ----------- ------ ------
latch: row cache objects 2,057,004 490,074 238 43.8 Concurrency
enq: US - contention 1,548,328 370,460 239 33.1 Other
Or when you investigate and found enq: US - contention is the cause of the performance of a session/database.
Changes
Cause
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In this Document
| Symptoms |
| Changes |
| Cause |
| Solution |
| References |