LI73147: IMPROVE FILTER FACTOR ESTIMATES FOR PREDICATES ON OLAP FUNCTION ROW_NUMBER()

DB2 Version 9.1 Fix Pack 7  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

• This fix will improve filter factor estimates for a predicate
  on an olap function, row_number().
  .
  For example:
  .
  select *
  from (  select t1.*,
                 row_number() over (partition by c1, c2, c3) as
  rownum
          from t1 ) a
  where a.rownum = 1;
  .
  We would compute better filter factors for the olap function
  predicate.
  

Local fix

Problem summary

• This fix will improve filter factor estimates for a predicate
  on an olap function, row_number().
  .
  For example:
  .
  select *
  from (  select t1.*,
                 row_number() over (partition by c1, c2, c3) as
  rownum
          from t1 ) a
  where a.rownum = 1;
  .
  We would compute better filter factors for the olap function
  predicate.
  

Problem conclusion

• module:  engn_sqno
  CSD >= V91 fixpack 6
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IZ15196

• APAR is sysrouted TO one or more of the following:

  LI73148

Modules/Macros

• ENG_SQNO
  

Fix information

• Fixed component name

  DB2 UDE ESE LIN

• Fixed component ID

  5765F4104

Applicable component levels

• R910 PSN

     UP