Oracle Scratchpad

November 28, 2008

Log file write

Filed under: Infrastructure,Performance,redo,Troubleshooting — Jonathan Lewis @ 9:04 am GMT Nov 28,2008

A few years ago, I wrote a note about a bug in 9i that made it difficult to decide whether or not you had a problem with the log writer (lgwr). The problem was that the time spent in wait event “log file parallel write” was not captured properly – so you were reduced to guessing whether the time spent in “log file sync” might actually be an indication of a log file write problem.

Time changes everything – including the available tools and levels of skill of the people doing the trouble – and I see that Riyaj Shamsudeen recently published a note about the same problem.

Riyaj approaches the problem from a different direction, using exactly the right tool for the task, to demonstrate the error directly (rather than relying on modelling, inference and a follow-up check with Metalink as I did in 2005).

[Update 30th Nov 2008:] Here’s another interesting article on a closely related topic from Christian Bilien – in this case from a 10g system.

1 Comment »

  1. […] Jonanthan Lewis – Log File Write […]

    Pingback by Log File Write And Waits « Vishal Gupta's Blog — June 18, 2011 @ 8:02 pm BST Jun 18,2011 | Reply

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