Types of history databases
A history database can be of either of two types.
- Query
- A query database collects and stores the data that is most commonly needed to monitor and report on the query activity of a system.
- Audit
- An audit database collects the same data as a query database, but stores the data in row-secured tables and digitally signs the data to prevent it from being changed.
An audit database is more secure than a query database, but this
improved security comes at a cost:
- With an audit database, queries on the history tables are subjected to row-level security checks. This decreases performance compared to a query database.
- Because an audit database uses row-secure tables, you must configure multi-level security. A query database does not use row-secure tables and so does not require multi-level security.
- If an audit database is used and the history data staging area exceeds its STORAGELIMIT value, the system stops, and the administrator must free up space and restart the system before users can resume activity. If a query database is used and the history data staging area exceeds its STORAGELIMIT value, the system continues to run.