Database Hang and Users Cannot Login; Errors in the Alert Log 'ORA-00494: enqueue [CF]'
(Doc ID 2351185.1)
Last updated on FEBRUARY 08, 2022
Applies to:
Oracle Database - Enterprise Edition - Version 11.2.0.4 and laterOracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database 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
Information in this document applies to any platform.
Symptoms
- Database hang and users cannot connect
- Alert log has CF enqueue error:
ORA-00494: enqueue [CF] held for too long (more than 900 seconds) by 'inst 1, osid 3106' - AWR shows high I/O waits:
- Waits by total wait time shows top wait as user I/O:1
Changes
Cause
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In this Document
| Symptoms |
| Changes |
| Cause |
| Solution |
| References |