A fix is available
APAR status
Closed as program error.
Error description
This APAR will change the default of zparm option QUERY ACCEL OPTION 9 introduced by APAR PH10758 to disable code used for incorporating the uncertainty factor (DSN_PREDICAT_TABLE.UNCERTAINTY) in the predicate filter factor estimate when there are insufficient statistics to determine whether to send a query to IBM Db2 Analytics Accelerator. Accelerator users who want to enable the uncertainty cost estimation will need to enable the new zparm to get this behaviour. Additional Keywords: ZSA45
Local fix
No work around available
Problem summary
**************************************************************** * USERS AFFECTED: * * All Db2 11 and Db2 12 for z/OS users * * of IBM Db2 Analytics Accelerator * * offload to execute queries with host * * variables or parameter markers. * * who have PH10758 (UI63176/UI63171) * * applied. * **************************************************************** * PROBLEM DESCRIPTION: * * PH13163 is the PE-fixing APAR of * * PH10758 and the PTFs UI63176 (V11) and * * UI63171 (V12). * * * * PH10758 introduced a new option, 9, * * to the Db2 subsystem parameter * * QUERY_ACCEL_OPTIONS. When the user * * specifies QUERY_ACCEL_OPTIONS with * * option 9, Db2 will not adjust the * * cost estimate even when 'uncertainty' * * is detected. By default, * * QUERY_ACCEL_OPTIONS does not specify * * option 9. * * * * PH13163 will switch the 'costing' * * behavior when QUERY_ACCEL_OPTIONS * * has option 9 and when * * QUERY_ACCEL_OPTIONS has the default * * value. When QUERY_ACCEL_OPTIONS * * has the default value, Db2 will not * * adjust the cost estimate even when * * 'uncertainty' is detected. When * * QUERY_ACCEL_OPTIONS specifies * * option 9, Db2 will adjust the cost * * estimate when 'uncertainty' is * * detected. * **************************************************************** * RECOMMENDATION: * * Apply corrective PTF when available. * **************************************************************** PH13163 is the PE-fixing APAR of PH10758 and the PTFs UI63176 and UI63171. PH10758 introduced a new option, 9, to the Db2 subsystem parameter QUERY_ACCEL_OPTIONS. When the user specifies QUERY_ACCEL_OPTIONS with option 9, Db2 will not adjust the cost estimate even when 'uncertainty' is detected. By default, QUERY_ACCEL_OPTIONS does not specify option 9. PH13163 will switch the 'costing' behavior when QUERY_ACCEL_OPTIONS has option 9 and when QUERY_ACCEL_OPTIONS has the default value. When QUERY_ACCEL_OPTIONS has the default value, Db2 will not adjust the cost estimate even when 'uncertainty' is detected. When QUERY_ACCEL_OPTIONS specifies option 9, Db2 will adjust the cost estimate when 'uncertainty' is detected.
Problem conclusion
PH13163 will switch the 'costing' behavior when QUERY_ACCEL_OPTIONS has option 9 and when QUERY_ACCEL_OPTIONS has the default value. IDAAV5R1/K IDAAV7R1/K SQLHOSTVAR SQLACCESSPATH
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PH13163
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
B10
Status
CLOSED PER
PE
YesPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2019-06-11
Closed date
2019-06-25
Last modified date
2019-07-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI63856 UI63859
Modules/Macros
DSNWZIFB DSNWZIFC DSNTIP8A DSNDQWPZ DSNTINST DSNDSPRM DSN6SPRM DSNXOGP
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
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:
01 July 2019