OTMA ACEE flood control enhancement

In IMS 14, OTMA is enhanced with the accessor environment element (ACEE) flood control function to prevent an excessive number of RACF® ACEEs from being stored in cache.

Previously, the number of ACEEs that were stored in cache could not be limited. An unlimited number of ACEEs stored in cache by OTMA and a high aging value for the ACEEs caused virtual storage in the IMS control region to run out.

This enhancement is delivered with APAR/PTFs PI81621/UI54243/UI54244.

With this enhancement, you can enable OTMA ACEE flood control in the DFSOTMA descriptor of the DFSYDTx member of the IMS PROCLIB data set. When you enable OTMA ACEE flood control, you limit the number of RACF user IDs, which in turn limits the number of ACEEs that are cached by OTMA. This in turn prevents virtual storage in the IMS control region from running out.

With OTMA ACEE flood control enabled, OTMA checks the expiration values of the least recently used ACEEs first to speed up the ACEE cleanup process.

With this enhancement, you can also specify the ACEEAGE parameter on the /SECURE OTMA command to define an OTMA ACEE aging value that overrides the aging value passed by OTMA clients. You can use the ACEEAGE parameter to define an aging value that is lower than the value passed by OTMA clients, thereby expediting the cleanup of OTMA ACEEs that are stored in cache.

Changes defining IMS

The DFSOTMA descriptor of the DFSYDTx member is enhanced with the following parameters:

TOACEE=NO|YES: Enables or disables the OTMA ACEE flood control function.
ACEEUSR=: When OTMA ACEE flood control is enabled, allows you to define the number of RACF user profiles that are stored in ACEEs.

Changes to commands

The following commands are enhanced:

The /DISPLAY OTMA command is enhanced with the following output fields:

ACEECT

Displays the total number of cached OTMA ACEEs for the OTMA server.

TOACEE

Displays whether OTMA ACEE flood control is enabled.
The /SECURE OTMA command is enhanced with the ACEEAGE parameter to allow you to define an ACEE aging value for OTMA clients.

For a list of the commands that are new or changed for this enhancement see the IMS commands row in the table in Documentation changes.

Documentation changes

The following table lists the publications that contain new or changed topics for the OTMA ACEE flood control enhancement. Publications that are not impacted by this enhancement are not included in the table.

Table 1. Links to topics that have new or changed content for this enhancement
Publication	Links to topics
Release planning	May 2017 enhancement PTFs Command enhancements overview OTMA ACEE flood control enhancement (new) (this topic)
System definition	Members of the IMS PROCLIB data set > DFSYDTx member of the IMS PROCLIB data set DFSOTMA descriptor syntax and parameters
Communications and connections	IMS Connect and TCP/IP communications > IMS Connect security support Specifying an OTMA ACEE aging value in the IMS Connect configuration member Open Transaction Manager Access (OTMA) > Enabling and using OTMA OTMA descriptors DFSOTMA descriptor Managing system resources and OTMA OTMA ACEE flood control (new) OTMA security > Specifying OTMA security Refreshing RACF ACEEs for OTMA
IMS commands	/DISPLAY OTMA command /SECURE command