Collecting statistics

Statistics describe the physical and logical characteristics of a table and its indexes. You should collect table and index statistics periodically for each active table. These statistics are used by the database manager to determine a good way to access the data. If the data has changed significantly, to the extent that the information last collected no longer reflects the actual table data, then performance can begin to deteriorate when users are accessing data.

Collect statistics at least once a week. You might also want to collect statistics after loading data on the system. For example, when you load data into an application group that uses Multiple Loads per Database Table, Content Manager OnDemand can add rows to an existing table. After the load completes, the information used by the SQL query optimizer does not reflect the latest updates to the table. Before you allow users to access the data, you should collect statistics on the table.

Content Manager OnDemand lets you collect statistics for all of the tables in the database with the ARSMAINT program. When you run the ARSMAINT program to collect statistics, it collects statistics on all of the tables in the database that have changed since the last time that you collected statistics. You can automate the collection of statistics by scheduling the ARSMAINT program to run with the appropriate options.

You can also manually collect statistics by running the ARSMAINT program from the prompt. See ARSMAINT for details about the parameters and options that you can specify.