A fix is available
APAR status
Closed as program error.
Error description
The Db2 V12 Function level 505 introduces improvements to the support for DECFLOAT columns to improve performance of mission critical applications. These improvements include the ability to specify DECFLOAT columns in an index and as a key in a primary or unique key. Db2 HPU exploits indexes for the index scan feature that may be triggered to process the ORDER clause of an unload statement. As Db2 HPU does not support indexes with DECFLOAT columns, it may fail when processing a logical unload with an ORDER clause which order criterion involves a DECFLOAT column and matches the key of an index on the involved table if the index scan feature is enable.
Local fix
If the problem occurs, it can be solved by disabling the index scan feature by adding the INDEXSCAN NO option to the UNLOAD statement.
Problem summary
**************************************************************** * USERS AFFECTED: Users of Db2 High Performance Unload * * for z/OS * **************************************************************** * PROBLEM DESCRIPTION: The Db2 V12 Function level 505 * * introduces improvements to the support * * for DECFLOAT columns to improve * * performance of mission critical * * applications. These improvements * * include the ability to specify DECFLOAT * * columns in an index and as a key in a * * primary or unique key. * * * * Db2 HPU exploits indexes for the index * * scan feature that may be triggered to * * process the ORDER clause of an unload * * statement. The index scan feature does * * not support indexes. Any attempt to use * * it in such a case leads to inefficient * * index scan feature reported the * * statistics bloc in the SYSPRINT dataset * * by IXSC 0% which means the index scan * * feature is uselessly run and reduces * * Db2 HPU performance where it should * * increase it, As a consequence, the * * index scan feature should automatically * * e disabled whenever the involved * * clustering index has a key involving a * * DECFLOAT column. * **************************************************************** * RECOMMENDATION: Apply the PTF. * **************************************************************** Disable indexscan when an index key involved DECFLOAT type
Problem conclusion
Code has been changed to fix this problem.
Temporary fix
Comments
APAR Information
APAR number
PH21189
Reported component name
DB2 HI PERF UNL
Reported component ID
5697F4400
Reported release
510
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2020-01-21
Closed date
2020-03-03
Last modified date
2020-04-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI68180
Modules/Macros
INZ$$PRM INZTDSC INZTVAR INZUTIB1 INZUTIB2 INZUTILC INZUTILK INZUTILL
Fix information
Fixed component name
DB2 HI PERF UNL
Fixed component ID
5697F4400
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:
12 February 2021