CICS facilities that use 64-bit storage
The CICS® facilities that use 64-bit storage and the amount of storage that each facility requires are listed. You can use this information when you estimate a suitable MEMLIMIT value for your CICS region.
The following table lists CICS facilities that use 64-bit storage and the relevant CICS storage subpools, and indicates the amount of storage that each facility requires. You can identify the facilities that you use in your CICS region that require 64-bit storage. You can then examine the storage requirement for those facilities and use this information to estimate a suitable value for the z/OS® MEMLIMIT parameter.
CICS facility | Storage use | CICS subpool for storage | Notes® |
---|---|---|---|
Application context data control blocks | 220 bytes for each program that is defined as an application entry point. | PGPPTE64 | |
Association data control blocks | Approximately 1 KB for each active task. | MN_ADCS | |
CICS management client interface (CMCI) | For the details to estimate storage requirements, see Estimating storage requirements for CMCI. | WU_64 | The storage is used for retained results and metadata. |
CICSPlex® SM API result sets | The size of the result set depends on the application. | CPSM_64 | For information about result sets, see Working with result sets. |
Console queue processing | 1 MB per subpool |
CQCQ_TR
CQCQ_XT |
|
Containers and channels | Limited to 5% of the MEMLIMIT value per transaction. | PGCSDB | The storage remains in use until the channel goes out of scope, or an application deletes the container or the channel. |
Event processing | EP_64 | The storage is used for control blocks for items in event capture queues. | |
Internal trace table | Minimum 16 KB
Controlled by
the TRTABSZ system initialization parameter.Maximum 1 GB Default 12288 KB (12 MB) |
MVS™ storage outside the CICS DSAs | CICS allocates a Memory Object of the maximum size but defines the unused area as Hidden storage. |
JVM servers |
Apart from the values in -Xmx and -Xcmsx, the amount of storage is variable. |
MVS storage outside the CICS DSAs | |
Loader control blocks | Variable |
LD_APES
LD_CPES LD_CSECT |
The storage that is used depends on the number of program load operations in the CICS region. |
Loader control blocks for installed application elements (IAE) | 368 bytes for each IAE | LD_IAES | Each installed application element represents a particular version of an application that is deployed on a platform. |
Main temporary storage | Minimum 1 MB
Controlled by the
TSMAINLIMIT system initialization parameter.Maximum 32 GB Default 64 MB |
TSDTN
TSMAIN TSMN0064 TSMN0128 TSMN0192 TSMN0256 TSMN0320 TSMN0384 TSMN0448 TSMN0512 TSMN0576 TSMN0640 TSMN0704 TSMN0768 TSMN0832 TSMN0896 TSMN0960 TSMN1024 TSQUEUE TSTSI |
TSMAINLIMIT specifies the maximum storage that can be used, and is limited to 25% of the MEMLIMIT value. The CICS statistics show actual use. |
Managed Platform | 1072 bytes for each user task |
DFHMPMDR
DFHMPPMB DFHMPTAS |
Storage in the DFHMPMDR and DFHMPPMB subpools is used for control blocks for
installed policies. It remains in use until the bundle that defines the policy is
disabled. Storage in the DFHMPTAS subpool contains the policy counters for a task. It is allocated for every user task if any polices are installed in the CICS region. The storage is freed at task end. |
Message tables | Minimum 3 MB for the message modules in English. Add 1 MB if the user message table is loaded. Add 3 MB for each additional language that is loaded. |
MVS storage outside the CICS DSAs | Message modules in English are always loaded. |
Node.js applications | Variable | MVS storage outside the CICS DSAs | |
Sockets domain | Stores the copy of the HTTPS data being sent. The size of the storage depends on the size of the HTTPS message being sent. | SOGNRL64 | This storage subpool is used if the sockets domain needs to copy the HTTPS message before it is sent. |
Static data item control blocks | Variable | MPSTAT | Used if a policy rule with an event action defines static data capture items. |
Storage allocation control blocks | Variable | MVS storage outside the CICS DSAs | Storage used depends on the amount of storage allocation activity in your system; for example, more storage is required for subpools that keep an element chain and that have many small records. |
Transaction dump trace table | Minimum 16 KB
Controlled by the
TRTRANSZ system initialization parameter.Maximum 1 GB Default 1024 KB |
MVS storage outside the CICS DSAs | CICS obtains this storage only when a transaction dump is produced. |
Web domain | Stores the HTTP body. The size of the storage used depends on the size of the HTTP body being processed. | WB64GNRL | Where possible, the web domain holds the HTTP body in 64-bit storage by using this subpool. |
Web domain | Internal buffer storage for HTTP outbound messages. The size of the storage depends on the size of the HTTP message being sent. | WBOUTB64 | Used by the web domain to obtain buffers and control blocks from 64-bit storage. |
z/OS XML System Services (XMLSS) parser I/O buffers | ML64GNRL | A number of facilities, including CICS web services, use the parser for XML parsing. |