Adaptive Switching Between Log Write Methods can Cause 'log file sync' Waits

(Doc ID 1462942.1)

Last updated on JANUARY 22, 2018

Applies to:

Oracle Database - Enterprise Edition - Version 11.2.0.3 and later
Information in this document applies to any platform.

The database version is 11.2.0.3
The log writer process on the database is blocking most of the other sessions and taking an average wait time of 10ms to commit.
On checking the hardware, the I/O wait time is very small from the hardware side
This means that all the time is on CPU processing the request.
Database is OLTP-based and has high commits/second
The same issue did not occur in 10g.
The problem seems to 'go away' temporarily after the database is restarted but ultimately returns after a few days.
AWR may show 'log file sync' waits as the highest wait:

The database was upgraded from 10.2.0.4 to 11.2.0.3.1.

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