Re: Differences between Undo and Rollback Segments?

If you have a retention time (number of seconds since 1st Jan 1980 (IIRC)) as the last commit time in an extent, then if you have a long running transaction that suspends, and another session that does lots of commits, you could get into a state where the last commit time on an extent is very old (because of the busy session) but the extent is still active (because of the suspended transaction).

I WOULD expect Oracle to deal with this properly, but it is the sort of silly little detail where someone may have overlooked the need for retaining an extent even though it's last commit timestamp was a long time in the past.

--
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Jonathan Lewis
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Mark D Powell wrote in message
<2687bb95.0212201007.1f55fa03_at_posting.google.com>...


>"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message

news:<atum6m$d9o$3$8302bc10_at_news.demon.co.uk>...


>>

>> BTW - do you have any indication of when

>> Oracle will run multiple transactions into an

>> Undo ?  I haven't seen it happen yet, and the

>> use of the retention map suggest that there

>> is a nasty trap waiting to be engineered if

>> it does.

>>

>

>Jonathan, are you willing to enlighten us on the trap?

>

>-- Mark D Powell --