> it's not good to have too many extents. how many is "too many"? what
> factors do you take into consideration for determining the "too many"
level?
I think it's hard to come up with a magic number -- basically, you are
trying to use the INITIAL & NEXT values of a segment's storage clause to
keep the number of extents small (say, under 100) since the extent
allocation itself represents some overhead & it is also true that a large
number of extents will slow down certain operations (such as DROPping the
object.) On the other hand, if you set INITIAL &/or NEXT to very large
values you may end wasting space if the segment in question never uses the
space allocated. It's a trade-off. Hopefully the develpers (or vendor in
the case of 3rd party software) will give you some guidance. If not, take a
look at the extents in the development DB & use that as a guide for
production. It's also a good idea to monitor extent allocations in
production & increase NEXT sizes for segments that are extending often.
Received on Tue Jan 22 2002 - 12:14:58 CST
