Long Wait on Log File Sync Wait Event with Message 'Log file sync switching to polling' and 'Warning: log write elapsed time'
(Doc ID 2372105.1)
Last updated on NOVEMBER 07, 2019
Applies to:Oracle Database - Enterprise Edition - Version 184.108.40.206 and later
Oracle Database Cloud Schema 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
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.
- High log file sync waits in AWR report:
Top 10 Foreground Events by Total Wait Time
Event Waits Total Wait Time (sec) Wait Avg(ms) % D B time Wait Class
log file sync 316,964 8864.2 28 31.3 Commit
log buffer space 34 3777.7 111108 13.4 Configuration
- There are following tracefile messages:
Log file sync switching to polling
Current scheduling delay is 1 usec
Current approximate redo synch write rate is 2 per sec
*** 2018-02-14 08:46:46.669
Warning: log write elapsed time 180076ms, size K B>>>>>>I/O spike 180 seconds for 2kb written.
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