Re: log file sync , log file parallel write

From: K Gopalakrishnan <kaygopal_at_gmail.com>
Date: 18 Dec 2006 23:17:49 -0800
Message-ID: <1166512668.987783.125680@80g2000cwy.googlegroups.com>

Not always (at least in RAC!!)

In a RAC environment, cache fusion transfers sometimes causes the log file sync event. This is due to the write ahead logging mechanism. When a foreground process requests a block from another instance, all the redo entries associated with the block must be flushed to disk prior to transferring the block. In this case, there is no commit involved, but buffer cahe synchronization and waits on the log file sync event.

>log file sync = commit.
> Consequently, if you state you can't change the app, you can't change
> the *number* of commits, but you can influence their *duration*.
>
> --
> Sybrand Bakker
> Senior Oracke DBA'- Hide quoted text -- Show quoted text -

Best Regards,
K Gopalakrishnan

Co-Author: Oracle Wait Interface, Oracle Press 2004 http://www.amazon.com/exec/obidos/tg/detail/-/007222729X/

Author: Oracle Database 10g RAC Handbook, Oracle Press 2006 http://www.amazon.com/gp/product/007146509X/ Received on Tue Dec 19 2006 - 01:17:49 CST