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Creating Proper Statistics on Siebel EIM Tables

This topic is part of Troubleshooting Siebel EIM Performance.

Use of the .IFB file parameter UPDATE STATISTICS is only applicable to IBM DB2 for z/OS. This parameter can control whether Siebel EIM dynamically updates the statistics of EIM tables. The default setting is TRUE. This parameter can be used to create a set of statistics on the EIM tables that you can save and then reapply to subsequent runs. After you have determined this optimal set of statistics, you can turn off the UPDATE STATISTICS parameter in the .IFB file (UPDATE STATISTICS is FALSE) thereby saving time during the Siebel EIM runs.

To determine the optimal set of statistics, you need to run several test batches and RUNSTATS commands with different options to see what produces the best results.

Before and after each test, execute the db2look utility in mimic mode to save the statistics from the database system catalogs. For example, if you are testing Siebel EIM runs using EIM_CONTACT1 in database SIEBELDB, then the following command generates UPDATE STATISTICS commands in the file EIM_CONTACT1_mim.sql:

db2look -m -a -d SIEBELDB -t EIM_CONTACT1 -o
EIM_CONTACT1_mim.sql

The file EIM_CONTACT1_mim.sql contains SQL UPDATE statements to update database system catalog tables with the saved statistics.

You can experiment with running test Siebel EIM batches after inserting the RUNSTATS commands provided in IBM DB2 for z/OS Options. After you find the set of statistics that works best, you can apply that particular mim.sql file to the database.

NOTE:  Do not forget to save statistics with db2look between runs.

IBM DB2 for z/OS Options

The syntax for IBM DB2 for z/OS commands provides more options, as follows:

• shrlevel change
• allow write access
• allow read access

The clauses allow read access and shrlevel change provide the greatest concurrency.