Re: rollback segment question

From: Steve Adams <steve.adams_at_ixora.com.au>
Date: Wed, 08 Dec 1999 23:19:33 GMT
Message-ID: <384edecf.34772139@news.eagles.bbs.net.au>

Hello Kal121,

My solid opinion is that 77 waits in a day is almost trivial, regardless of the ratios or any other consideration.

The number of active transactions in the instance at any one time can be seen by counting the number of rows in V$TRANSACTION. In Oracle8, you can get a high-water mark for this from V$RESOURCE_LIMIT. In Oracle7, you can get the same info from X$KTCXB with the following query.

select
  'transactions' parameter,
  count(*) setting,
  count(decode(ktcxbflg, 0, null, 0)) hwm,   to_char(
    100 * count(decode(ktcxbflg, 0, null, 0)) / count(*),     '99999'
  ) || '%' usage
from
  sys.x$ktcxb
/

Regards,
Steve Adams

http://www.ixora.com.au/

http://www.oreilly.com/catalog/orinternals/

http://www.christianity.com.au/

On Wed, 08 Dec 1999 17:10:27 GMT, kal121_at_yahoo.com wrote:

>I've heard differing opinions on rollback segments:
>
>Everyday our system seems to have more "waits" on the rollback
>segments, however the ratio of waits to gets is well under 1%. For
>example, yesterday we had a total of 52 rbs waits, today there is 77.
>Does this mean I should keep adding rollback segments - or not worry
>about is since the "get ratio" is still greater than 99%? There are 20
>rollback segs currently. I'd like an solid opinion on this.
>
>Also, how can I measure the number of transactions being performed on
>the database for a given time period? I'd really like to know how to
>measure this!
>
>Thanks
>
>
>Sent via Deja.com http://www.deja.com/
>Before you buy.
Received on Wed Dec 08 1999 - 17:19:33 CST