Fixes are available
APAR status
Closed as program error.
Error description
When intra_parallel is enabled, a sort operation may be parallelized amongst many processes. Control information that is shared amongst the concurrent processes is protected by a latching protocol. However, one piece of control information is read without protection of the latch. Since this value may be modified at the same time by another process, reading this transient value may produce and invalid value. In this case the invalid 0 value was used as the denomentator in a division resulting in an crash. This would occur in very rare timing conditions. The stack of the crashing process would contain entries similar to: Signal #8 (SIGFPE) - (FPE_INTDIV:Integer divide by zero.) <StackTrace> sqlsEstimateNumberOfRowsForGrowth sqlsIncreaseSortBufferSize sqlsResizeSortBufferBeforeInsert sqlsinsr sqlrsinsr
Local fix
no workaround
Problem summary
When intra_parallel is enabled, a sort operation may be parallelized amongst many processes. Control information that is shared amongst the concurrent processes is protected by a latching protocol. However, one piece of control information is read without protection of the latch. Since this value may be modified at the same time by another process, reading this transient value may produce and invalid value. In this case the invalid 0 value was used as the denomentator in a division resulting in an crash. This would occur in very rare timing conditions. The stack of the crashing process would contain entries similar to: Signal #8 (SIGFPE) - (FPE_INTDIV:Integer divide by zero.) <StackTrace> sqlsEstimateNumberOfRowsForGrowth sqlsIncreaseSortBufferSize sqlsResizeSortBufferBeforeInsert sqlsinsr sqlrsinsr
Problem conclusion
First fixed in DB2 UDB Version v9.1, FixPak 8 and v9.5 FixPak FP4.
Temporary fix
Comments
APAR Information
APAR number
IZ40474
Reported component name
DB2 UDB ESE SOL
Reported component ID
5765F4102
Reported release
910
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2008-12-19
Closed date
2009-10-08
Last modified date
2009-10-08
APAR is sysrouted FROM one or more of the following:
IZ40473
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
DB2 UDB ESE SOL
Fixed component ID
5765F4102
Applicable component levels
R910 PSY
UP
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Document Information
Modified date:
08 October 2009