To ensure a safe database operation and good performance, two other activities must be done from time to time: Verify and Update Statistics.
Verify can be executed while the database is operational. It checks the consistency of internal chains within the B* trees used. If inconsistencies are discovered, the database must be restored. A Verify is recommended before each complete backup of the database.
Verify in COLD mode (i.e., before a Restart of the serverdb) has an additional property: pages wrongly recorded as used since an irregular end of database operation are released to the free space management.
Update Statistics determines the number of rows in tables and the selectivity of individual columns. The ADABAS optimizer needs these specifications to determine the best strategy for the processing of complex SQL statements. If the sizes or the value assignments in the database have changed considerably, a new Update Statistics must be performed. Update Statistics should be executed once a week.
If ADABAS determines differences between the optimizer assumptions from the last Update Statistics and the current state of a table, it attempts to perform an implicit Update Statistics. If there are conflicting locks, this attempt might be aborted, so that the implicit Update Statistics is not a complete equivalent of the explicit Update Statistics.