LOG FILE SYNC WAITS SPIKES DURING RMAN ARCHIVELOG BACKUPS (Doc ID 1229104.1)

Last updated on OCTOBER 26, 2016

Applies to:

Oracle Database - Enterprise Edition - Version 10.1.0.2 and later
Information in this document applies to any platform.

Symptoms

A decrease in transaction throughput was noticed at the same time as RMAN was backing up archivelogs.

Ashdumps were taken at the time of the slowdown (see <Note 555303.1>) and the following query showed a correlation between time 'log file sync' wait and 'CF-enqueue' spikes:


SQL> select to_char(sample_time,'HH24:MI:SSxFF'),
            event,
            count(*),
            sum(time_waited)
     from ashdump
     group by sample_time,event,time_waited
     order by sum(time_waited);

Cause

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