Analyzing fragmentation exceptions for index databases

Analyze the fragmentation exceptions that were detected for index databases.

Before you begin

Ensure that you can access the Sensor Data Statistics report that contains the latest sensor data. If you cannot access this report, run the FF DB Sensor Printing utility to generate the report.

About this task

In the following procedure, you will analyze the fragmentation exception that you received for HIDAM primary indexes, secondary indexes, or HALDB partitioned secondary indexes.

The only fragmentation exception for index databases is EXCESSIVE_INDEX_CI_OR_CA_SPLITS. You will identify the relevant data elements to understand the condition of the index database.

By completing this task, you will identify the type of fragmentation symptoms that occurred and the index data set for which the exception was reported.

Procedure

Follow the instruction to analyze the EXCESSIVE_INDEX_CI_OR_CA_SPLITS exception.
Exception class name: EXCESSIVE_INDEX_CI_OR_CA_SPLITS
This exception applies to VSAM KSDSs such as HIDAM primary index databases, the primary data set of secondary index databases, and partitioned secondary index databases. This exception does not apply to VSAM ESDSs such as the overflow data set of secondary index databases.
This exception indicates that the number of control interval (CI) splits, control area (CA) splits, or both are high, and that the VSAM KSDS file is fragmented.
An excessive number of CI splits and CA splits might affect the I/O performance efficiency of applications that perform a massive amount of sequential reading. For information about the effects of an excessive number of CI splits or CA splits, see the topic "Optimizing Free Space Distribution" in z/OS® DFSMS Using Data Sets.
Locate the following data elements in the Sensor Data Statistics report:
DBX_NUM_CI_SPLIT
DBX_PCT_NUM_CI_SPLIT
The values for these data elements indicate the number of split CIs and the percentage of split CIs compared to the total number of CIs.
DBX_NUM_CA_SPLIT
DBX_PCT_NUM_CA_SPLIT
The values for these data elements indicate the number of split CAs and the percentage of split CAs compared to the total number of CAs.
You have now obtained information about the current database state that caused this exception. You will use this information later to determine the appropriate action to resolve the exception.

What to do next

If you received other exceptions that belong to other exception categories, see the following topics to determine your next step:

If EXCESSIVE_INDEX_CI_OR_CA_SPLITS is the only exceptions that you received, Resolving fragmentation exceptions for index databases.