Re: allocated vs. used pages (large extents)

> > > I hate thinking of something after I've already posted an answer: > Oh BTW - order by tabname ...No I didn't come back in from the parking lot to email and post that, it occured to me that I had another opportunity to make an ass out of myself... I assumed that you were familiar with Unix and dynamic allocation of disk space. It occured to me on my way out that this may not be the case. Lately I keep running into folks from the mainframe world who have never heard of what we consider simple concepts. You mentioned Oracle and quite a few Oracle folk come from those environments. Depending on your data sets it may not be desirable to fix your table extents so rigidly. When your table grows beyond it's reserved size (read first extent) the engine is going to allocate another chunk of disk sized according to systables.nextsize (NEXT SIZE from your CREATE TABLE statement). If you have stable tables - which are not growing then you have no problem, but if you have a growing table then you will wish to allocate it room to grow - by sizing that first extent AS WELL AS the next extent. If you don't specify a next size then informix assumes 16 - perhaps not desirable. This may leave you with a table which is fragmented all over your disk. The concept here is to manage growth using those two parameters, NOT to allocate enough disk space so that you never overfill things, AND not to plan so that every 2 weeks you have to rebuild the table because of disk fragmentation issues. Rebuilding tables takes them down - not desirable in a high availability environment. I'm sure you are aware of all that and that I've just insulted your intelligence - in which case I apologize - but you never know. I am also not implying that Oracle has rigid disk allocation strategies - I haven't the foggiest (nor do I care). cheers j. _____________________________________________________________________________ Jack Parker - Hewlett Packard, DMD/IS Boise, Idaho, USA jparker@hpbs3645.boi.hp.com Back in Boise _____________________________________________________________________________ My pappy said "Son, you're gonna drive me to drinking if you don't stop driving that hot rod Lincoln." - CC _____________________________________________________________________________ Any opinions expressed herein are my own and not those of my employers. _____________________________________________________________________________