PK53475: TASK STUCK IN FCIOWAIT USING KSDS FILES

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• A program running on an open TCB issuing file control requests
  against local KSDS LSR files can occationally hangs with an
  FCIOWAIT.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Users                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: The problem occurs when running         *
  *                      programs defined as                     *
  *                      CONCURRENCY(THREADSAFE) on a CICS       *
  *                      regions with STGPROT=YES. If these      *
  *                      programs issue file control requests    *
  *                      against local VSAM files, tasks may     *
  *                      stall with an FCIOWAIT.                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The VSWA trace showed that the FCIOWAIT was due to waiting for
  asynchronous ENDREQ to be posted. VSAM executes ENDREQ requests
  syncrhonously so we should not wait for the request to be
  posted. However as the ENDREQ reused an ECB which was usually in
  a posted state, the wait was in effect posted immediately. When
  running a loaded system on multiple open TCBs the ECB may be
  reused between the ENDREQ and the WAIT, so might not be in a
  posted state. If this is the case the task will hang.
  

Problem conclusion

• A change was made to convert VSAM SYN requests to ASY to improve
  threadsafe performance on open TCBs. A check is now made for
  ENDREQ requests. These will always run SYN on the open TCBs.
  

Temporary fix

• FIX AVAILABLE BY PTF ONLY
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UK30523

Modules/Macros

•    DFHFCVR
  

Fix information

• Fixed component name

  CICSTS V3 Z/OS

• Fixed component ID

  5655M1500

Applicable component levels

• R500 PSY UK30523

     UP07/10/26 P F710

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.