hi,
If ur database is in OLTP environment, it is recommended to have small block size. Becoz the queries will extract only small amount of data and it is advisable to keep the data in small blocks. If u have a big block size, unnecessariy u will be reading unwanted data into the cache.

If u have a DSS environment(Data whearhousing), where ur database is query intensive, it is recommended to have big block size, so that oracle can read more amount of data into the cache in one shot.
And again if u r table contain objects of big size like graphics files, it is recommended to have a big block size
Keeping small blocks in this case would mean lot of I/O and CPU overheads.


As a DBA, it is very important to decide abt the block size when u create the database; since this directly influences the performance. Once u have created the database u cant change the size of the block unless u recreate the database.

Regards
Sonia

[Edited by sonia on 04-08-2002 at 12:37 AM]