Re: Large RollbackSegment

Well, a shrink of a data file is done with the 'alter database datafile 'name' resize Xm' command. And a shrink of a rollback segment can be done with the 'alter rollback segment blah shrink to Ym' command. The first command will fail if it encounters any actual segments on the way down to a smaller datafile size. And the second might not actually get down to the size you specify if it would involve getting rid of bits of a rollback segment that are actually in use.

But the real question is why has one rollback segment ballooned in size? Because ordinarily, you'd expect Oracle's automatic allocation of transactions to available rollback segments to mean that, over time, all rollback segments should be of approximately the same size.

Do you have something that is suddenly taking it upon itself to pick which rollback segment to go into (with the 'set transaction use rollback segment blah' command)? Have you recently performed particular batch-type updates? Has someone been doing bulk loads of data? If so, are these legitimate activities? And if they are, why has no special provision for housing their rollback in specially large rollback segments been made?

There's stuff about sizing rollback segments on my website (Tips, Administration). Maybe that might help. But there's more to this than meets the eye. Perhaps.

Regards
HJR

--
Resources for Oracle: http://www.hjrdba.com
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"Roland Carlsson" <roland.c_at_swetravel.se> wrote in message
news:3bf24b25$1_at_d2o21.telia.com...


> Hi!

> I have got a really large rollbacksegment. It's about twice the size of

the


> rest of the database and have of some reason grown very quickly the last

> month. Is there a rollbackAll command I can do to be able to shrink the

size


> of the databasefile??

>

> Thanks in advance

> Roland Carlsson

>

>