Fragmentation of free space is *impossible* with uniform extent sizes. It is merely *rare* with automatic extent sizes, but definitely *achievable*. With automatic extent sizes, the database has a small number of extent sizes to choose from, but as soon as you have more than 1 choice, fragmentation is possible. I have had very good (better than ever expected!) results with automatic extent sizes myself, but I *can* imagine how these *could* be used to fragment a tablespace. I not certain how to do it, but this is probably a pretty good recipe for fragmentation: Create a bunch of small segments. Grow them to 100x or 1000x their initial size (allocating lots of extents of varying sizes). Drop. Repeat. Happily, few (sane) applications will follow a pattern like this. For exactly this reason, I prefer to use uniform extent sizes whenever I can find one that fits reasonably. It is not always a viable option, though. On Tue, Jul 28, 2009 at 12:52 PM, Schauss, R. Peter (IT Solutions) < peter.schauss@xxxxxxx> wrote: > How did the product cause free space fragmentation? > > - Peter Schauss > > -----Original Message----- > From: oracle-l-bounce@xxxxxxxxxxxxx > [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Powell, Mark D > Sent: Tuesday, July 28, 2009 2:04 PM > To: Oracle L > Subject: RE: Locally managed tablespaces - autoallocate vs. uniform > > ... > ... > With one exception where the product actually managed to create a free > space fragmentation condition the feature works well. For that one > product we converted the tablespace to using uniform extents and have > not had an issue since. > > > -- Mark D Powell -- > Phone (313) 592-5148 > > -- > //www.freelists.org/webpage/oracle-l > > > -- Cheers, -- Mark Brinsmead Senior DBA, The Pythian Group http://www.pythian.com/blogs