CICS Transaction Server Performance & Tuning

This course takes systems programmers through the main components of CICS, explaining at each stage how various parameters, design concepts, CICS facilities, operating system facilities and network facilities affect the performance of CICS systems. Where GDPR regulations allow, attendees are encouraged to bring statistics and/or resources that relate to CICS performance issues from their own systems, in order to gain added value from the course.

This course is also available for exclusive one-company presentations, either on-site or live over the Internet via RSM's Virtual Classroom Environment service.

Virtual Classroom Environment dates - click to book!

UK Start Times

2 April 2024 24 July 2024

What is a 'Virtual Classroom Environment'?


What do I need?

  • webcam
  • headphones with microphone
  • sufficient bandwidth, at least 1.5 Mb/s in each direction.

What you will learn

On successful completion of this course you will be able to:

  • explain how performance is affected by parameters and design concepts
  • manipulate CICS facilities to optimize performance
  • describe the impact of z/OS facilities on CICS performance
  • explain the impact of network features on performance.

Who Should Attend

Systems Programmers.


CICS systems programming experience.


4 days

Fee (per attendee)

£2550 (ex VAT)


This includes free online 24/7 access to course notes.


Hard copy course notes are available on request from

at £50.00 plus carriage per set.

Course Code



Introduction to CICS Performance

Performance objectives; Response times; Types of Waits; Resource load; Why tune?; Methodology; CICS and the applications; Measurement tools; Benchmarking tools; What resources to tune; Storage; CPU cycles; I/O reduction; Terminal I/O; Checklist for tuning; Making a change; Goal for tuning; Key CICS measurement statistics; Processor cycle (CPU) checklist; Virtual Storage checklist; Real Storage checklist; I/O tuning checklist.

z/OS interface

Resource hierarchy; Central storage; Auxiliary storage; Address space; Operating System; CICS private area; CICS region layout; Data spaces; Checking the z/OS storage; Coupling Facility; VSAM Record Level Sharing; Coupling Facility Data Tables; TS datasharing concepts; TCBs; OPENTCBS; CPU utilization; OPENAPI; Concurrency required; CICS & Real Storage; Other OS areas; Recommendations.


CICS dispatching; Double chains; CICS dispatching TCBS; Mode switching; Maximum Task (MXT); Recommendations; Statistics; Transaction Class (TCLASS); TRANCLASS; Task Priority & PRTYAGE (SIT); Transaction priority; Priority Age; Formula; Empiric evidence; Transaction Priority (PRTYAGE); Region exit interval ICV; Runaway task time ICVR; Multi-tasking; DTIMOUT; SIT parameters; Limit conditions; Other transaction definitions; Transaction Isolation; Dispatcher statistics; End of day statistics; Output from stat transaction; z/OS interface questions.

Storage Management

Problems with storage; 31-bit storage; System Queue Area And Extended SQA; Link Pack Area And Extended LP; z/OS Common Service Area; Private And Extended Private Area; 64-bit storage; MEMLIMIT; Region size; RMF; Common Storage; Common Areas; The CICS Private Area; High Private Area; LSQA; Scheduler Work Area; Subpool; z/OS Storage above the CICS region; z/OS Storage within the CICS region; CICS kernel storage; Kernel changes; DSAs CICS V5.1 onwards; DSA limits; DSA extent sizes; Fragmentation; DSA parameters; DFHSMUTL; PAM examples; Solutions to DSA problems; CICS JVM Execution Environment; CICS LE/370; New SIT parameters; CICS LE/370 CEEROPT; CLER transaction; Storage - questions.


Loader Domain; CICS program compression; The new philosophy; Target calculation; DFHRPL; Dynamic DFHRPL; OTE enhancements - threadsafe; Compression trace; Virtual Lookaside Facility (VLF); Library LookAside (LLA); SIT parameter LLACOPY; Loader statistics.

Network - VTAM & TCP/IP

Network performance; Network components; High Performance Option (HPO); RAPOOL; Statistics; RECEIVESIZE/SENDSIZE; IOAREALEN; MSGINTEG; ICV; SIT parameter; AUTOINSTALL; AUTOINSTALL statistics; Problems with shutdown; Data compression; Statistics; Unsolicited statistics; Accessing CICS from the web; CWS overview; Performance study; CWS RDO; TCPIPSERVICE definition; BACKLOG; IPADDRESS; TSQPREFIX; SSL(NO|YES|CLIENTAUTH); AUTHENTICATE(NO|BASIC|CERTIFICATE|AUTOREGISTER|AUTOMATIC); CWS Secure Sockets Layer; Web Support; Storage requirements; SSL enablement; SSL SIT parameters; SSLDELAY; MAXSSLTCBs; Full SSL handshake; Doctemplate; Channel & Containers; New ABEND codes; EXEC commands; CICS Web Support; Network review.


A typical CICSPlex; MRO sessions; ISC sessions; System entries; Workload management; Generic resource names; MRO long running mirrors; MROBTCH; IPCONN.


File structures; Alternate index; VSAM fundamentals; VSAM myths and legends; Changing environments; Obsolete parameters; VSAM KSDS; Free space; CI LOCK; Disk space utilization; VSAM LISTCAT; Important LISTCAT fields; Premature Control Area splits; Non Shared Resources (NSR); Default buffering; NSR index buffers; Eliminating Index; I/O; NSR index buffers calculation; NSR data buffers; Local Shared Resources; LSRPOOL; How many buffer pools?; Number of defined LSR pools; LSR VSAM Threadsafe file distribution; VSAM threadsafe; Data tables; User maintained; Shared data table; Performance benefits; SDT performance issues; VSAM RLS; RLSACCESS(NO|YES); Record Level Sharing (RLS); RLS restrictions; VSAM RLS I/O path; VSAM RLS sub-components; Buffer management; 31-bit and 64-bit buffer management; Performance issues; Contention issues; CICS & RLS performance; Coupling Facility Data Tables (CFDTs).

z/OS Logger

CICS SIT parameters; CICS V4 AKPFREQ considerations; Log Manager concepts; The z/OS System Logger; CICS Log Manager domain; The Coupling Facility; DASD-ONLY logging; Statistics available; CICS TS activity keypointing; Journal models; Coupling Facility example; DASD model example; Logger statistics; SMF 88 record fields.

Transient Data

Extrapartition; Intrapartition queues; Recovery serialization; Transient Data; Sample statistics; Buffers and strings.

Temporary Storage

API commands; Main vs Aux vs Coupling Facility; Auxiliary; TST replacement; TS Coupling Facility pool; TS list structures; Small queues vs large queues; TS server JCL; Statistics; Temporary Storage tuning area; TS MAIN vs. TS AUX; Server stats; Temporary statistics.

CICS - Db2 Interface

Defining Db2 connections with CEDA; CICS TS TCB allocation; How the dispatcher selects an L8/L9 TCB; Defining Db2 entries with CEDA; Example trace FORCEQR=YES; Example trace program concurrency(threadsafe); Threadsafe file control; Performance; Performance TCB; Threadsafe code; Threadsafe CICS commands; Load module summary report; Detail report; Example DFHEISUP; Accounting; Statistics; DSNC display statistics.


DBCTL; Database Resource Adapter; DBCTL TCB support; DBCTL virtual storage planning; Statistics; Open Transaction Environment (OTE) support.

© RSM Technology 2022