I think there are 2 basic things to consider for "efficiency" and the results will be system and site dependent. Its worth re-iterating though that I think the efficiency or otherwise of autoextend from a performance viewpoint is way down the list of priorities. (it was just interesting at a quiet time). First is, *overall *how efficient do you want the allocation of space to be. The best result will be achieved if you never autoextend but size exactly correctly to begin with :) In general the fewer file extension operations you do the better, but its a declining win. Second, how much do you want to delay any individual transaction that triggers a file extension event? here the opposite applies, the more small file extensions you have the shorter each individual event will be. I have some figures and a sample script for others to test/critique etc at http://orawin.info/blog/2012/01/04/proof-by-extension/ cheers Niall On Sat, Dec 24, 2011 at 12:38 PM, Sreejith S Nair <sreejithsna@xxxxxxxxx>wrote: > > Hello friends, > > I have been asked this question by one of our fellow team member. The > question goes as follows. > > Oracle database 2 nose RAC 11.2.0.2 on Solaris 10 wih ASM > > Case 1. You size the database which is expected to grow 50GB in one month > for say 6 months by creating 10 data files with maxbytes(32GB) without > AUTOEXTEND so that they have no need to AUTOEXTEND. > > Case 2. You add two datafiles with an initial size of say 100M with > AUTOEXTEND on , on next 512M. You keep on monitoring the ASM disk space > and add storage when the disk gets full. > > The question was which one is efficient. Forget the file management > overheads and all. The question is just based on system performance or > 'cost' for AUTOEXTEND ing the datafiles. From my understanding it doesn't > really makes much difference unless your system is very very busy , though > I do not know any metrics or how to explain how busy the system is for > this to make a difference > > Please add your valuable comments on this. > > > Cheers, > Sreejith > > -- > Sent from my iPhone-- > //www.freelists.org/webpage/oracle-l > > > -- Niall Litchfield Oracle DBA http://www.orawin.info -- //www.freelists.org/webpage/oracle-l