PK84125: Improved access control performance on DB2 for z/OS

APAR status

• Closed as program error.

Error description

• Without the "FOR READ ONLY" clause, DB2 considers the SQL
  read-only if it is not update-able. Examples are if there are
  table joins or if there is a sort (for DISTINCT, ORDER BY etc),
  or if the query contains WITH UR or FETCH FIRST. For other
  cases, the SQL is considered "ambiguous" - DB2 cannot determine
  whether the SQL will be updated or not. Certain optimizer
  transformations, such that required for this SQL, are
  dis-allowed for ambiguous SQLs.
  Another way for an ambigious cursor to be considered read-only
  is when the BIND parameter CURRENTDATA is set to NO.
  

Local fix

Problem summary

• The database optimizer cannot optimize some queries
  efficiently, if he has to prepare for possible subsequent
  updates to the result set.
  

Problem conclusion

• The affected queries have been extended by clause "FOR READ
  ONLY", so can optimize this query efficiently.
  
  Failing Module(s):
     Database
  
  Affected Users:
     All users
  
  Version Information:
      Portal Version(s): 6.0.1.5
       Pre-Requisite(s):
        Co-Requisite(s): ---
  
      Portal Version(s): 6.1.0.0
       Pre-Requisite(s):
        Co-Requisite(s): ---
  
      Portal Version(s): 6.1.0.1
       Pre-Requisite(s): PK75758
        Co-Requisite(s): ---
  
      Portal Version(s): 6.1.0.2
       Pre-Requisite(s):
        Co-Requisite(s): ---
  
  Platform Specific:
     This fix applies to all platforms.
  
  A fix is available from Fix Central:
  
  http://www.ibm.com/eserver/support/fixes/fixcentral/swgquickorde
  r?apar=PK84125&productid=WebSphere%20Portal&brandid=5
  
  You may need to type or paste the complete address into your Web
  browser.
  

Temporary fix

Comments

APAR Information

• 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

  WEBSPHERE PORTA

• Fixed component ID

  5724E7600

Applicable component levels

• R60J PSY

     UP

• R610 PSY

     UP

• R61A PSY

     UP

• R61B PSY

     UP