PH03945: FEDERATED QUERY WITH CASE/WHEN EXPRESSIONS ARE SLOW WHEN USING NETEZZA AS SOURCE DB

APAR status

• Closed as fixed if next.

Error description

• Simple CASE/WHEN statements are prevented from being pushed
  down to the source when using Netezza as Source Database. Due
  to this, performance for queries using CASE/WHEN statements may
  be degraded.
  For example:
  Case 1: query in when-condition
  --------------------------------------
  CASE
  WHEN col1 =
      (SELECT
         DISTINCT col1
       FROM
         tab1
       WHERE
         col2 = -1
      )
  THEN 1
  ELSE 0 END AS OUTPUT
  .
  This APAR adds the required support to push down the following
  operations:
  .
              operator "="
              operator "||"
              expression CASE/WHNLIST/WHEN
              function SYSIBM.COALESCE()
              function SYSIBM.DATE()
              function SYSIBM.VARCHAR()
              function SYSIBM.INTEGER()
              function SYSIBM.TIME()
              function SYSIBM.ROUND()
  

Local fix

Problem summary

• See problem description
  

Problem conclusion

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

Applicable component levels