A fix is available
APAR status
Closed as program error.
Error description
After an ALTER table got a dsnt375i deadlock and needed to rollback, this lead to an abend04e in dsnkflok at erqual1001 . The abend had the following title: DSN ,ABND=04E-00C90101,U=uuuuuuu ,M=N ,C=121.DMC -DSNIRSVP,M=DSNTFRCV,LOC=DSNIDM .DSNKFLOK:1001 . During the backout of the ALTER, Index Manager was freeing the Fast Traverse Block structures and came acrosss another task holding a lock on the FTB . . Additional keywords: FTB p-lock . vrace1001 DB2FTB/K
Local fix
Turn off FTB. Defer the ALTER and materialise during REORG later, for example use DDL_MATERIALIZATION to ALWAYS_PENDING .
Problem summary
**************************************************************** * USERS AFFECTED: * * All Db2 12 for z/OS users with indexes that * * are eligible for Fast Traverse Block (FTB) * * optimization. * **************************************************************** * PROBLEM DESCRIPTION: * * After an ALTER table got a dsnt375i * * deadlock and needed to rollback, this * * lead to an abend04e in dsnkflok at * * erqual1001. * * * * During the backout of the ALTER, Index * * Manager was freeing the Fast Traverse * * Block structures and came across * * another task holding a lock on the * * FTB. * * * * Additional keywords: * * FTB p-lock vrace1001 * * DSNKFTIN ERQUAL5002 * **************************************************************** * RECOMMENDATION: * * Apply corrective PTF when available * **************************************************************** The rollback of the ALTER table, also caused a rollback of an ALTERed index (triggered by the ALTER table). The rollback of the ALTERed index marked the Index Descriptor (IXD) for removal, but the FTBs associated with the index were not freed. Then later processing on the member (where the rollback of the ALTER index occurred), could encounter a previous FTB plock being held, since the FTB(s) were not freed immediately during the rollback.
Problem conclusion
Index Manager code has been modified to immediately free FTB structures and their associated FTB plocks, whenever an IXD is being marked for removal.
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PH11204
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
C10
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2019-04-18
Closed date
2019-09-12
Last modified date
2020-06-30
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI65307
Modules/Macros
DSNKIXDB DSNKTRAV DSNKLOD2 DSNB1CPP DSNKFTOM DSNKUSET DSNKINSL
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RC10 PSY UI65307
UP19/09/27 P F909 ¢
Fix is available
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Document Information
Modified date:
01 July 2020