Re: Deriving Intial & next parameters

it is a matter of storage utilization and your data distribution on the data files of oracle!

lets say that you have a table of 4 columns and 100 byte long records ( at Max, assuming no null values since they take 1 byte or all varchar fields are utilized their Max size with varchar(2) having 3 bytes of storage usage) you can calculate the land requirement of your table in current position. lets say an extent of 100K is more than enough ( please consider pctfree, pctused parameters to find the minimum unused space in a block and find out the size of blocks ( 2K or 4K probably) to calculate the unused space in each block and within 100k extent 50-2K blocks) so , when your first extent is fully used up next extent will be taken from data file elsewhere ( where available )
that is a problem of fragmentation. as the number of extents increase probably your data is more distributed
on data files.
next, other side of the coin is that if you give an extent of 200K to a lookup table having only few items you can not use other space on that extent. And do not forget that both initial and first next extent is taken from data files when a table or schema object is created. Do not forget indexes!! they have a record size of indexed columns + rowid length .

I always try to keep small number of extents. with a possibility of using all.

nmk_1970_at_hotmail.com wrote in message <884629662.1801388041_at_dejanews.com>...
>Hi netters,
>
> Is there any predefined rule to derive the above parameters
> while creating the rollback segment while creating a new database.
>
> TIA
>
>/muralikrishna
>
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Received on Tue Jan 13 1998 - 00:00:00 CST