Re: Runaway SMON process

It has been my experience that this can happen when you drop a segment (or multiple segments) that contain *lots* of extents. SMON will most likely try to coalesce the free space. I've seen where this coalescing can take high amounts of CPU and a very long time to complete. To see if this is happening in your case, issue the following:

SELECT count(*) FROM sys.fet$;

Some time later, issue the same query. If the count is going down, then SMON is coalescing free space. SMON will cease the behaviour you described once it is done coalescing.

HTH,
Brian  

Osbit wrote:
>
> I'm having a problem with the SMON process on my Oracle instance. It has
> suddenly become the busiest process on the system, consuming about 50% CPU
> on a system that is doing nothing else at all. Disk activity is at almost
> zero, only writing about 2.4Kb / sec to three data areas.
> If I try and shutdown the database it just hangs there, so I tried a
> shutdown abort and then a restart with the same result, a hang.
> I can't figure out what the SMON process is doing as I've not worked with
> Oracle for that long.
>
> Can anyone help out the new guy ?
>
> Thanks in advance.
Received on Wed Dec 12 2001 - 08:22:25 CST