Displaying Table Access Statistics

Use

In the workload monitor, you can display the workload in differentanalysis views which highlight the workload from a particular perspective. One of these aspects is the question of which transactions have accessed which database tables, and how often.

Since the number of statistics records greatly increases by logging table accesses of this type, this option is deactivated by default. You should only activate it temporarily for individual analyses, and for individual transactions, since performance problems can occur in the statistics collector otherwise.

Prerequisites

To display table access statistics for individual transactions, you first need to activate this:

Start the Workload Monitor by calling transaction ST03.
Ensure that you are in the ExpertUser Mode.
Choose Collector & Performance DB → Statistics Records & File → Online Parameters → _{Dialog Step Statistics.}
The Change Runtime Parameters of Statistics dialog screen appears.
You can change the online parameter stat/tabrec, which specifies the maximum number of table access statistics subrecords that the kernel is to write for each transaction step. The N most resource-intensive accesses of a transaction step are stored.

If you only want to activate the table access statistics for certain transactions, you can specify a maximum of five transactions in the online parameters stat/tcode1 to stat/tcode5. The table access statistics are then only produced for these transactions.

Caution
Change the parameter stat/tabrec only temporarily for individual analyses. It must be set to 0 (zero) at all other times. Otherwise, the number of statistics records increases significantly, which can lead to performance problems in the statistics collector.

Procedure

Start the Workload Monitor by calling transaction ST03.
In the Workloadtree, choose the instance and period to be analyzed.
Choose _{Analysis Views →
_{Table Access Statistics.Note
If no table access statistics are available for certain instance, the
system does not display the icon for the table access statistics.}}
The system displays the usual output area, in which the requested table access statistics are displayed.

Result

The output area contains two tab pages with the following characteristics:

Tab Page	Description
Tables	The database tables that the activated transactions accessed are displayed with the most important load data (number of selected, read, and modified data records, access time). If you choose a table by double-clicking it, another screen appears, showing the transactions that accessed this specific table.
Transactions	The activated transactions are displayed with the most important load data concerning table accesses (see above). If you choose a transaction by double-clicking it, another screen appears, showing the tables that this specific transaction accessed.

Workload Monitor start page