Wait event log file parallel write

My Notebook. Home About. Log file sync wait event Oct 25 oracle Viewed times. Once LGWR knows that its write requests have completed, it will post the user session to notify it that this has completed. The user session waits on 'log file sync' while waiting for LGWR to post it back to confirm all redo it generated have made it safely onto disk. When the one-third threshold is met, the LGWR process performs a background write if it is not already active. And the amount of redo entries may be too much for the LGWR to handle at one time, causing extended log file parallel write waits.

So the idea is to stream the LGWR writes. LEBSZ for the log block size. Typically, it is bytes. At this size, the LGWR process becomes lazy and normally writes only on transaction terminations sync writes or when it wakes up from its three-second timeouts.

This method is not without overhead. The LGWR write operation requires the redo copy and redo writing latches. So a more active LGWR process will increase the load on these latches. Make sure you obtain a baseline before implementing the change. Previous page. Table of content. LGWR is typically the only process to see this wait event. It will wait until all blocks have been written to all members.

Also see on log file parallel writes:. Oracle wait analysis. Oracle log file single write. Tuning options: 1. Like this: Like Loading Leave a Reply Cancel reply Enter your comment here Fill in your details below or click an icon to log in:.

Email Address never made public. Follow Following.