A fix is available
APAR status
Closed as program error.
Error description
Customer has applications that use multiple jobs to process a PHIDAM database with each job only processing one partition. The application does this by maintaining its own table of the High Keys for each of the partitions. When they want to process a selected partition (for example, partition 5) they will issue a GHU call using a GT operator using the High Key value from the previous partition. (4 in this example). This will cause IMS to position the job at the first key within the partition they are going to process. This caused a U0796 abend for one of the jobs. A GHU with a GT operator was specified and returned the next highest key that matched the request. However on the following REPL call to update that segment, the U0796 abend was issued. The customer was was able to reproduce the U0796 using DFSDDLT0. Further analysis revealed there were no records in the first PHIDAM partition. The only record was the X'FF' key. The actual data that was returned from the GHU call was the first record in the next partition. Using the customer's scenario, the U0796 was recreated at SVL and the culprit was linked to V12 APAR PM53588.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All IMS V12 Full Function HALDB PHIDAM users * * with multiple partitions issuing a GHU call * * followed by a REPL call. Also, this problem * * occurs only after apar PM53588 / ptf UK82804 * * is applied. * **************************************************************** * PROBLEM DESCRIPTION: When attempting to replace ( REPL ) the * * first root segment in the second and * * subsequent HALDB partitions after * * issuing a GHU call to retrieve the * * root segment, the REPL call fails with * * an ABENDU0796, which indicates an * * attempt to replace a segment when the * * lock on the segment is not held. * **************************************************************** * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF * **************************************************************** After apar PM53588 / ptf UK82804 is applied, an attempt to replace ( REPL ) the first root segment of the second and subsequent partitions of a HALDB fails with an ABENDU0796. Code added by apar PM53588 / ptf UK82804 forced the lock on the all X'FF' key to be gotten and released when crossing the HALDB partition boundary. When the lock on the all X'FF' key is released flag JCBREPET is not reset. DFSPSEL0 is then called to select the next partition. Because flag JCBREPET was not reset, the expected root segment in the next partition is retrieved, but the enqueue call to get the lock on the root segment is skipped. When the REPL call is then attempted, the ABENDU0796 occurs.
Problem conclusion
GEN: KEYWORDS: *** END IMS KEYWORDS *** The following module has been modified to correct the reported problem: ************ * DFSDLR00 * ************ Code has been added in the BYKEY routine, after label KEYEND50, to reset flag JCBREPET after the dequeue of the lock on the all X'FF' key is done. This will then allow the enqueue of the lock on the root segment retrieved in the next partition to be done correctly.
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PM81487
Reported component name
IMS V12
Reported component ID
5635A0300
Reported release
201
Status
CLOSED PER
PE
YesPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2013-01-25
Closed date
2013-03-29
Last modified date
2013-05-06
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Modules/Macros
DFSDLR00
Fix information
Fixed component name
IMS V12
Fixed component ID
5635A0300
Applicable component levels
R201 PSY UK93036
UP13/04/02 P F304 «
Fix is available
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Document Information
Modified date:
14 December 2020