RE: Rollback Segment tuning

Hi Stephane,

I run the script and I have

OPTIMAL = 5 * ceil(max(v$rollstat.aveactive) / 4 / sys.ts$.blocksize)* sys.ts$.blocksize / 1024

the result is 0 K for my optimal. : )

regards,
Sinardy

-----Original Message-----
Sent: 03 June 2002 16:53
To: Multiple recipients of list ORACLE-L

>
>Hi all,=0D
>=0D
>How to find out the smallest (minimal) transaction
>size from Dictionary vie=
>w or base tables =0D
>I try to set my OPTIMAL rollback segment base on
>smallest transaction size =
>to prevent ora-1555. since shrinking rollback
>segments may cause ora-1555.=
>=0D
>=0D
>=0D
>Thanks =0D
>=0D
>Sinardy=0D
>--=0D

Smallest ? Are you sure that you do not mean greatest ? Opinions diverge about OPTIMAL. As far as I am concerned I like it on databases where you may have occasionally very big changes. Look at V$ROLLSTAT. You have there the average amount of rollback segment used, as well as the high-water mark. You can use those values to derive something looking common-sensical. Alternatively, I think that there is in the 'X-rated' section of the Oriole site (http://www.oriole.com) something to set OPTIMAL automatically (don't worry, even with this name it contains nothing illegal in Singapore :-)). Even if you do not run the script as is, looking at what it does - and possibly questioning it - may give you the answer you are looking for.

Regards,

Stephane Faroult
Oriole

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Author: Stephane Faroul
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Author: Sinardy Xing
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