Rollback Segment Question

From: Jeanne <jcman_at_SPAMMEBABY.worldnet.att.net>
Date: 13 Feb 1999 23:08:14 GMT
Message-ID: <7a50ku$5s@bgtnsc03.worldnet.att.net>

I am currently studying for the 2nd OCP exam (DBA), and I am a little confused about what I am reading about rollback segments.

All the examples in the array of books strewn across my desk say that 2 transactions can share an extent in a rollback segment, but that blocks within an extent can only store one transaction.

But then they start talking about the round-robin circular search for new extents, and if the "extent" to which they've circled around contains active transactions, then it must grab a new extent, because that extent is tied up. But I thought that extent was share-able, only individual blocks within an extent weren't share-able. I am failing to see how these "blocking sessions" arise.

Does anyone see my confusion? Thanks. Received on Sat Feb 13 1999 - 17:08:14 CST