Estimating database size

There is a minumum size indicated for the version of database you are creating. Refer to the installation guide for the appropriate version when determining database size.

When estimating database size, keep in mind that it is easy to increase the size of a database but difficult to decrease it. To decrease the size of a database, you must delete the database and then recreate it.

To estimate the size of a database, consider:

Anticipated size of its largest objects—tables and indexes
Space for planned views, stored procedures, defaults, rules, and triggers
Size of the transaction log
Additional space for expansion based on anticipated activity

The Adaptive Server system procedure sp_estspace helps you estimate table and index space requirements based on the definition of a specific table. To use sp_estspace:

On a nonproduction database, create the tables and indexes you anticipate the new database will contain. For information about creating tables and indexes, see Chapter 17, “Managing User Tables,” and Chapter 23, “Managing Indexes.”
Use a utility such as Interactive SQL to open a session with Adaptive Server.
Run sp_estspace for each table, and add the results. For details on running sp_estspace, see the Adaptive Server Reference Manual.

The size of the transaction log depends on the type and quantity of transactions and the frequency of backups. As a starting point, allocate 10-25% of the overall size of the database for the transaction log.