Resolving space use exceptions for HISAM and SHISAM databases
Resolve the space use exceptions that you received for your HISAM and SHISAM databases.
Before you begin
Ensure that you have completed the analysis steps for HISAM and SHISAM exceptions and that you have identified the possible causes of the database exceptions. If you have not yet analyzed the space use exceptions, see Analyzing space use exceptions for all full-function database types.
Procedure
If you receive space use exceptions, and if you identify an out-of-space condition in
database data sets as a result of analyzing the space use exceptions, consider resolving the
exception condition by taking the following actions:
- If you also receive fragmentation exceptions, and if you identify excessive fragmentation of IMS free space or the existence of many deleted segments, consider reorganizing the database. Reorganization will resolve the fragmentation and increase usable IMS free space in the data sets; subsequently, new segments can be added to the database.
- After you analyze the exceptions that you received, if you determine that reorganizing the database will not create sufficient IMS free space, and if you have not applied a Segment Edit/Compression exit routine, consider applying the routine. For information about applying the routine, see the topic "Segment Edit/Compression exit routines" in IMS Database Administration.
If the out-of-space conditions are not resolved by these actions, consider changing the database
structure or increasing the DASD resources. The method you apply depends on the results of the
analysis steps as follows:
Tip: Depending on the status of the data set, applying several
of the following methods can be an effective approach to resolving the exceptions. Before making any
changes to your environment, evaluate all the methods in the following list and determine the best
approach to resolve the condition.
- If the out-of-space condition is caused by a primary-space-used-up condition (that is, the data set has only primary space, and the size of used space is reaching the size of the primary allocated space), and if the data sets allocation size is smaller than the maximum size (4 GB or 8 GB), increase the size of the allocated space. For instructions for increasing the size of allocated space, see the topic "Changing the amount of space allocated" in IMS Database Administration.
- If the out-of-space condition is caused by a data-set-full condition (that is, the
size of the data set is approaching its maximum size of 4 GB), changing the DBD definition and then
restructuring the database will typically resolve the condition.
Consider the following methods to resolve a data-set-full condition:
- If your HISAM database has only a primary data set, add an overflow data set. When you add an overflow data set, be aware that I/O counts for accessing database records also increase.
- Split the database into several smaller databases.
- If the out-of-space condition is caused by an extent-resources-used-up condition
(that is, when the data set cannot be expanded), typically, changing the data set allocation
definitions and reorganizing the database will resolve the condition.
Consider the following methods to resolve an extent-resources-used-up condition:
- If the data set has reached the data set extent limit, and if the DASD volumes have enough space, increase the primary and the secondary extent sizes for data set allocation.
- If the DASD volume does not have enough space, or if the data set has reached the maximum number of extents that is allowed for that volume, increase the number of DASD volumes.