Re: Adding 2nd rollback segment

rickp_at_crl.com (Rick Poepping) wrote:

>Has Oracle changed the requirement that you have to add a 2nd rbs to the
>system tablespace before being able to add additional rbs in their own
>tablespace??? I know this used to be the case back in 7.0.16. I had
>heard that it was no longer true in 7.2.2. So I tried it out. Took
>already existing database with extra rbs exisiting outside system tspace;
>deleted these, tried to recreate and it worked. Did same again, this
>time bouncing the database before trying to recreate, still successful.
>Couldn't find anything in docs or release notes. Thought I'd try this on
>one of our 7.1.6 databases. Successful again. Is this really indicatine
>of a change?? Or is the fact that I went through the 'add 2nd system rbs,
>now add outside rbs, then del 2nd system rbs, and go merrily on your way'
>effort to set up the outside rbs before trying this test, coloring my
>results? I'd like to know if anyone has confirmation that the ol' 2nd
>system rbs shuffle is no longer necessary. Has anyone added additional
>rbs outside the system tspace on a newly created database without first
>haveing to add a 2nd rollback segment in the system tablespace. I guess
>I could try this myself but I'd rather have one of you tell me :).

Well, on 7.1.6, I created a new database from scratch using CREATE ... and then added tablespaces and 4 additional rollback segments and all went fine... I didn't create any rollback segment in the SYSTEM tablespace, although the installation script for 7.1.6 (probably inherited) still does so.

This has been somewhat confirmed when (at an Oracle training center) we created a database without having to shuffle between rollback segments.

They told us that the rollback segments were needed because rollback segments (when created) have MINEXTENTS to 2, and this was the reason Oracle needed another rollback segment to record that transaction in. That rollback segment could not be SYSTEM, because it's reserved for transaction in the system tablespace.
Creating a rollback segment in tablespace SYSTEM led Oracle to use the rollback segment SYSTEM, ending that strange recursion between existing and soon-to-be rollback segments. Once done that, that new rollback segment could be used to record the transaction that created the new rollback segments. (At least, I've been told so...:)

>Thanks,
 

>Rick
>--
>Rick Poepping Just my Opinions.
>St. Louis, MO USA Keep it Simple.
>rickp_at_crl.com Friend of Bill W.

Standard disclaimers apply Received on Tue Feb 20 1996 - 00:00:00 CET