A fix is available
APAR status
Closed as new function.
Error description
When the data to be retrieved by DB2 is only meant for reading, a good practice consists in specifying the FOR READ ONLY clause which allows DB2 to optimize its behavior and performance when processing the involved SELECT statement. DB2 HPU implements this good practice by adding the FOR READ ONLY clause to the SELECT statements specified in the UNLOAD command. However, in very rare situations, adding the FOR READ ONLY clause unexpectedly causes DB2 to choose an irrelevant access path thus leading to decreased performance. To circumvent this access path issue, DB2 HPU should be fitted with a parameter that allows to request the FOR READ ONLY clause not to be added. Please contact IBM Support for details if interested in this feature. PB45878
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: Users of IBM DB2 High Performance Unload * * z/OS. * **************************************************************** * PROBLEM DESCRIPTION: When the data to be retrieved by DB2 is * * only meant for reading, a good * * practice consists in specifying the * * FOR READ ONLY clause which allows DB2 * * to optimize its behavior and * * performance when processing the * * involved SELECT statement. DB2 HPU * * implements this good practise by adding * * the FOR READ ONLY clause to the SELECT * * statements specified in the UNLOAD * * command. * * However, in very rare situations, * * adding the FOR READ ONLY clause * * unexpectedly causes DB2 to choose an * * irrelevant access path thus leading to * * decreased performance. * * To circumvent this access path issue, * * DB2 HPU should be fitted with a * * parameter that allows to request the * * FOR READ ONLY clause not to be added. * * pb 45878 * **************************************************************** * RECOMMENDATION: APPLY the PTF. * **************************************************************** N/A (enhancement).
Problem conclusion
Temporary fix
Comments
APPLY the PTF.
APAR Information
APAR number
PI65342
Reported component name
DB2 HI PERF UNL
Reported component ID
5697F4400
Reported release
430
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-07-05
Closed date
2016-08-08
Last modified date
2016-10-07
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Modules/Macros
INZCRXSM INZCRXSQ INZUTILK
Fix information
Fixed component name
DB2 HI PERF UNL
Fixed component ID
5697F4400
Applicable component levels
R430 PSY UI39950
UP16/08/12 P F608
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.
[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSAUUV","label":"IBM Db2 High Performance Unload for z\/OS"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"4.3.0","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]
Document Information
Modified date:
12 February 2021