How can I calculate the future size of my database? It will be for WAP Portal and we expect 4.7 TPS and 8,000,000 transactions per month. I know it depends very much on my create tablespace options, INITIAL and NEXT extent options etc., but could you tell me more tips?
First, I don't worry about INITIAL and NEXT extent sizes anymore. Create your tablespaces as Locally Managed Tablespaces with the AUTOALLOCATE method and let Oracle manage the extents for you. Today's Oracle DBA does not worry about extent sizing any more.
You indicated that you expect about 8 million transactions per month. Do you have any idea how many bytes you'll need for one transaction, on average? You might need to come up with some sample data to figure that out. Once you know how much space an average transaction requires, then multiply times 8 million for one month's space requirements. That will give you a rough estimate for your tablespace size. You can extrapolate further for one year's worth of data, etc. Once you have an estimate, you know how big to create your tablespace.