A fix is available
APAR status
Closed as program error.
Error description
With a DB2 command, you cancelled some threads that were owned by a CICS region. These threads were protected threads that were not being used by a CICS transaction. At time of cancel, CICS issues the following message / dump: . DFHAP0002 CICSAPPL A severe error (code X'3255') has occurred in module DFHD2D2 . . Following that the CICS region is back to normal for a couple hours until tasks in this CICS region, as well as in other applications connected to DB2 start having SQL calls hang. This is caused by DB2 reaching cthread max . That causes SQL calls to hang while queued in QT* status in DB2 as there are no more available threads. An unusually large number of threads are threads in TD status owned by the CICS region that issued the DFHAP0002 message. . In the DFHAP0002 dump, the 'DB2=3' formatter shows that the CSUB owned by the CEX2 task has as CSUB trace showing the following as its last 2 entries: . 1F00024C C1E2E2D6 00000000 00000000 *...<ASSO 2000024C 5CD9C5C3 0000004E 00E50013 *...<*REC . Those entries show a successful ASSOciate , followed by the abend04E reason 00E50013 indicative of the cancel. . Then in a dump taken later after tasks have hung up, if you find in the 'DB2=3' output on 00024C , you get lots of hits like this one: . 6300024C C1E2E2D6 00000000 00F31101 *...<ASSO.....3.. . This shows task 24 trying and failing to associate to a protected thread it wants to terminate. The reason 00F31101 means that the D2 TCB (on which CEX2 is running) is already associated to a different thread. That thread would be the one it successfully ASSOciated to just prior to the abend04E reason 00E50013 caused by the cancel. This prevents the CEX2 from terminating any protected threads. Eventually that causes DB2 to reach cthread max, at which point this CICS and other DB2 applications start having SQL calls hanging in DB2 .
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All * **************************************************************** * PROBLEM DESCRIPTION: Message 'DFHAP0002 A severe error error * * (code X'3255') has occurred in module * * DFHD2D2' is received following the DB2 * * cancel of a protected thread. * **************************************************************** * RECOMMENDATION: * **************************************************************** A DB2 protected thread is in the process of being terminated by CEX2. After successfully associating the D2 TCB to that thread, a DB2 Cancel occurs. The cancel leads to the D2 TCB suffering an abend04E, which subsequently causes the x'3255' error within DFHD2D2. As a consequence, the DB2 subsystem can reach its CTHREAD limit, causing the system to become unresponsive. Additional keywords: 04E S04E
Problem conclusion
DFHD2D2 has been amended such that, within its recovery routine, if it has been called during a terminate_thread, a call to issue_db2_dissociate is made.
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
**** PE13/03/12 FIX IN ERROR. SEE APAR PM79809 FOR DESCRIPTION **** PE13/01/17 FIX IN ERROR. SEE APAR PM80818 FOR DESCRIPTION
APAR Information
APAR number
PM54748
Reported component name
CICS TS Z/OS V4
Reported component ID
5655S9700
Reported release
600
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2011-12-20
Closed date
2012-03-27
Last modified date
2013-04-09
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
PM57244 UK77435 UK77436
Modules/Macros
DESD2D2 DFHD2D2
Fix information
Fixed component name
CICS TS Z/OS V4
Fixed component ID
5655S9700
Applicable component levels
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:
09 April 2013