Re: Process and sessions overhead

From: <>
Date: Tue, 8 Mar 2011 18:14:48 +0000

We had the same issue with log file sync. There are multiple hidden parameters adjusted with process parameter and one should be carefull with processes parameter. On our case we kept memory same increased process from 400 to 500 and started to see log file syncs unfortunatelly I cannot say that's 100 percent the cause because to fix the issue even we adjusted sga target by %25 just to keep the percentage same but we also did 11g upgrade on the same day and everything sorted.

I can't also be sure because we also see io slowness on another db sharing same san and could not get a decent answer from storage guys during the issue (they already knew we increased the parameter without necesary memory adjustment so they did not even bother to check)

I also could not find any 10g reference for causing log file sync


-----Original Message-----
From: Niall Litchfield <> Sender: Date: Tue, 8 Mar 2011 17:56:49
To: K Gopalakrishnan<> Reply-To: Cc: <>; <> Subject: Re: Process and sessions overhead

Its a surprise to me that log file sync should be affected by the size of the process table, rather than the number of active processes (or private redo strands presumably?)

On 8 Mar 2011 17:14, "K Gopalakrishnan" <> wrote:


Other than the usual minimal memory overheads, there is significant impact on

  1. Log File Sync Wait times
  2. Calculated Value of MBRC

Starting from 10gR2, MBRC is auto tuned. The value of processes is taken in to consideration (along with buffer cache,etc) while calculating the MBRC. So I would exercise caution while playing with these parameters.


On Tue, Mar 8, 2011 at 11:07 AM, Niall Litchfield <> wrote:
> Or I c...

Received on Tue Mar 08 2011 - 12:14:48 CST

Original text of this message