08 August, 2007

LGWR and 'log file sync waits'

Kevin Closson has posted an insightful note on LGWR -- why sometimes the wait event 'log file sync' does not mean Redo Log File Write (ie I/O) waits. LGWR spends time in waiting on writes that it has posted but also in returning to post the sessions waiting on *it* to the effect that the writes have completed. It is the second part of the LGWR time that is the "processing" time which may not be getting enough CPU !

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