A fix is available
APAR status
Closed as program error.
Error description
When running a vendor RELOAD utility for several areas in the same DEDB, an excessive number of MSGIGW10077I messages occurred indicating deadlocks. This occurred during the step that issued a CHANGE.DBDS DB() AREA() ICON command. . If several CHANGE.DBDS for DBDSs that are in the same full function or HALDB or for the same AREAs that are in or AREA deadlocks can occur when attempting to update the DB record in RECON. If enough jobs are involved this can lead to an unending set of deadlocks and retries. This is in part because the CHANGE.DBDS processing gets the DB record with a share level lock and then, if it is determined an update is needed for that record, it will get an exclusive lock before doing the update. If two jobs do this at the same time, I deadlock occurs. If several jobs are involved we can get into a situation were all the jobs eventually become the deadlock victim and then retry. This can continue endlessly
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All V13 IMS DBRC PRA user will be affected. * **************************************************************** * PROBLEM DESCRIPTION: Excessive number of RLS deadlocks when * * multiple CHANGE.DBDS commands are * * processed in parallel. * **************************************************************** * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF * **************************************************************** When running a vendor RELOAD utility for several areas in the same DEDB, an excessive number of MSGIGW10077I messages occurred indicating deadlocks. This occurred during the step that issued a CHANGE.DBDS DB() AREA() ICON command. If several CHANGE.DBDS for DBDSs that are in the same full function or HALDB, or the several AREAs in the same DEDB, deadlocks can occur when attempting to update the DB record in RECON. If enough jobs are involved, this can lead to an unending set of deadlocks and retries. This is in part because the CHANGE.DBDS processing gets the DB record with a share level lock and then, if it is determined an update is needed for that record, it will get an exclusive lock before doing the update. If two jobs do this at the same time, a deadlock occurs. If several jobs are involved we can get into a situation where all the jobs eventually become the deadlock victim and then retry and this will continue endlessly.
Problem conclusion
GEN: KEYWORDS: *** END IMS KEYWORDS *** DSPURI60 is changed to issue a slightly different message if the retry error was hit for a IDALKADD request. It will issue the DSP1190 message with a 'LKADD' request type if that was the last request. Also, if it was a timeout for LKADD, only issue the message every 25 times instead of every 5 times. DSPPRAB is changed to add a new message threshold constant PRAB_MSGTHOLD_LKADD used to special case timeout errors for the IDALKADD request. DSPURM60 was changed to get an EXclusive lock on the DSPRLOCT calls for DB and AAUTH records. DSPUSTB2 defines new MSGDSP1190. ================================================================ ZES1310700 - THE FOLLOWING TEXT DESCRIBES THE DOC CHANGE: - A new DBRC message is obtained for this apar. Please use the following text description for the new DBRC MSGDSP1190W. DSP1190W A request to obtain a VSAM lock on a record has timed out nnnn times. Explanation An attempt by DBRC to obtain a VSAM lock for serialization purposes has repeatedly timed out. A lock request might time out repeatedly for one of the following reasons: *DBRC instances from multiple IMS systems are performing similar actions, such as might occur when a large number of utilities are running in parallel. *A DBRC instance is processing a long-running request, such as a LIST.RECON command. System Action Processing continues. System programmer response Issue the DISPLAY SMS,URID(ALL) command to determine if a DBRC instance is holding a lock for an excessive amount of time. If one is, consider cancelling that job. If the timeouts are not caused by one of the previously listed reasons, collect a dump from all DBRC instances and call IBM support.
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PM79774
Reported component name
IMS V13
Reported component ID
5635A0400
Reported release
300
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2012-12-27
Closed date
2013-03-01
Last modified date
2013-10-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
012AC3 UK92135
Modules/Macros
DSPURI60 DSPURM60 DSPUSTB2
Fix information
Fixed component name
IMS V13
Fixed component ID
5635A0400
Applicable component levels
R300 PSY UK92135
UP13/03/13 P F303
Fix is available
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Document Information
Modified date:
14 December 2020