Re: Troubleshooting ORA-01555 while using AUM

Pls. see below:

"Tech Geek" <Tech_Geek_at_Gawab-IHateSpam.com> wrote in message news:6Qw0c.19711$6K.4704_at_nwrddc02.gnilink.net...
>
> --- My bad. Please read as zeros, instead of non-zeros.
>
>
> > Could you supply more information about under exactly what
circumstances
> > the 1555 is happening in your case ?
>
> This database is being used by end-users for short transactions 24x7 and
> some adhoc batch jobs, which update/insert new records and also does some
> SELECTS. Mostly, the batch jobs and the daily export job run at time of
the
> day, ends up with Ora-1555.

I prefer to use StatsPack to figure out how large the undo TS should be but let's try and use the V$UNDOSTAT for the same purpose. Let's forget about those two columns (UNXPSTEALCNT/UNXPSTEALCNT) and take look at 'undoblk' and 'maxquerylen'.

Assuming the max value of undoblk is 10000 8K blocks in 10 minutes (0.13 MB/sec) and the max value in 'maxquerylen' is 7200 sec, then _each_ of your undo segments should at least be 940 MB in order to avoid the 1555 error. For ten segments, it'll amount to 9.4 GB.

VC Received on Sun Feb 29 2004 - 20:46:24 CST