Fixes are available
DB2 Version 9.1 Fix Pack 4a for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 4 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 7 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 5 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 6 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 6a for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 7a for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 8 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 9 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 10 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 11 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 12 for Linux, UNIX and Windows
APAR status
Closed as program error.
Error description
Due to changes in the DB2 optimizer code that started in DB2 9.1 a very complex query that used to work fine before an upgrade to DB2 9.1, may return the following warning after the upgrade: SQL0437W Performance of this complex query may be sub-optimal. Reason code: "1". SQLSTATE=01602. Explanation: The statement may achieve sub-optimal performance since the complexity of the query requires resources that are not available or optimization boundary conditions were encountered. The following is a list of reason codes: 1 The join enumeration method was altered due to memory constraints
Local fix
Two options to Workaround the issue. Set the DB2_REDUCED_OPTIMIZATION registry variable to YES db2set db2_reduced_optimization=yes or Reduce the current query optimization level (e.g. set current query optimization 2)
Problem summary
Users Affected: All Problem Description: Query may return a warning message SQL0437W after upgrading to Fix Pack 10 or later Error Description: Due to changes in the DB2 optimizer code that started in Fix Pack 10, a query that used to work fine before the upgrade, it may return the following warning after the upgrade: SQL0437W Performance of this complex query may be sub-optimal. Reason code: "1". SQLSTATE=01602. Problem Summary: Query may return a warning message SQL0437W after upgrading to Fix Pack 10 or later Error Description: Due to changes in the DB2 optimizer code that started in Fix Pack 10, a query that used to work fine before the upgrade, it may return the following warning after the upgrade: SQL0437W Performance of this complex query may be sub-optimal. Reason code: "1". SQLSTATE=01602. Explanation: The statement may achieve sub-optimal performance since the complexity of the query requires resources that are not available or optimization boundary conditions were encountered. The following is a list of reason codes: 1 The join enumeration method was altered due to memory constraints
Problem conclusion
Problem was first fixed in version 9 fixpack 4 (s071028)
Temporary fix
db2set db2_reduced_optimization=yes or Reduce the current query optimization level (e.g. set current query optimization 2)
Comments
APAR Information
APAR number
IY93789
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
2007-01-19
Closed date
2008-02-20
Last modified date
2011-07-20
APAR is sysrouted FROM one or more of the following:
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
R810 PSN
UP
R820 PSN
UP
R910 PSN
UP
R950 PSN
UP
Document Information
Modified date:
07 January 2022