How much jvm affects space & performance of DB????

Question

Hi ,
as i know , there are some objects created in system tablespace or something else in the DB after installing jvm.
My question is how much space those object occupted and how those changes affect on the original DB ????
Thanks
Stephen

Answer 1

If you measure the performance as the time required to allocate the initial 600 GB data file plus the time to do the load and compare that to allocating a small file and doing the load, letting the data file autoextend, it's unlikely that you'll see a noticable difference. You'll get far more variation just in moving 600 GB around than you'll lose waiting on the data file to extend. If there is a difference, allocating the entire file up front will be slightly more efficient.
More likely, however, is that you wouldn't count the time required to allocate the initial 600 GB data file since that is something that can be done far in advance. If you don't count that time, then allocating the entire file up front will be much more efficient.
If you may need less than 600 GB, on the other hand, allocating the entire file at once may waste some space. If that is a concern, it may make sense to compromise and allocate a 500 GB file initially (assuming that is a reasonable lower bound on the size you'll actually need) and let the file extend in 1 GB chunks. That won't be the most efficient approach and you may waste up to a GB of space but that may be a reasonable compromise.
Justin