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PK85822: GARBAGE COLLECTIONS ARE NOT INITIATED ANYMORE AFTER MIGRATION TO JAVA 5 09/06/03 PTF PECHANGE

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APAR status

  • Closed as program error.

Error description

  • Tasks CJGCs are attached in order to initiate a GC (garbage
collection) process after reaching the GC_HEAP_THRESHOLD value,
but the GC isn't performed successfully anymore after migrating
from JAVA 1.4.2 to JAVA 5.

The code in DFHSJCS that attaches the CJGC transaction is saving
the transaction token returned by XMAT at the wrong offset with-
in the SJTCB block. It is using offset x'518' instead of x'51C'.

When CJGC starts up program DFHSJGC runs and does some basic
checking to ensure it has been correctly invoked. One check is
to compare its own transaction token with the one saved in the
SJTCB block of the JVM that is supposed to have garbage collec-
tion run on it. Due to token being saved at the wrong offset in
the SJTCB block this check always fails and DFHSJGC issues EXEC
CICS RETURN without every attempting to do a System.gc().

Local fix

  • not available.

Problem summary

  • ****************************************************************
* USERS AFFECTED: All CICS Users.                              *
****************************************************************
* PROBLEM DESCRIPTION: Attempts to schedule garbage            *
*                      collection for Java 5 fail.             *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
Over time CICS schedules CJGC tasks to perform garbage
collection. However, the scheduled garbage collection isn't
doing anything. Although CJGC is being attached it isn't
calling the JVM to perform a System.gc() call. This is due
to the transaction token being stored at offset x'518'
instead of at x'51C'. As the token does not match that
which CJGC is expecting CJGC assumes another task is taking
care of garbage collection and returns without calling the
JVM.

PK59577 failed to ship DFHSJCL leading to the problem.

Problem conclusion

  • UK35003  UK35008  UK35009
The updated version of DFHSJCL has been shipped in this PTF.

Temporary fix

  • FIX AVAILABLE BY PTF ONLY

Comments

  • ž**** PE10/06/18 FIX IN ERROR. SEE APAR PK77018  FOR DESCRIPTION

APAR Information

  • APAR number

    PK85822

  • Reported component name

    CICSTS V3 Z/OS

  • Reported component ID

    5655M1500

  • Reported release

    500

  • Status

    CLOSED PER

  • PE

    YesPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-05-04

  • Closed date

    2009-06-25

  • Last modified date

    2010-06-18

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

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

    UK47823 UK47824 UK47825

Modules/Macros

  •    DESSJCS  DFHSJCL

Fix information

  • Fixed component name

    CICSTS V3 Z/OS

  • Fixed component ID

    5655M1500

Applicable component levels

  • R503 PSY UK47825

       UP09/07/22 P F907

  • R500 PSN UK47823

       UP09/07/22 P F907

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.

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Document Information

Modified date:
18 June 2010

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