IC75588: INFORMIX OUTER JOINS TAKE SLOWER PATH THAN ANSI OUTER JOINS

APAR status

• Closed as program error.

Error description

• Informix OUTER joins may take a slower query path than ANSI
  outer joins.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All 11.50 users.                                             *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * An Informix outer join query may have worse performance than *
  * equivalent ANSI JOIN query under the following conditions:   *
  *  - query has multiple level 0 tables, e.g., t1, t2           *
  *  - query has at least one level 1 table, e.g., t3            *
  *  - join predicate exists between t3 and one level 0 table,   *
  * e.g., t1.c1 = t3.c3                                          *
  *  - join predicate does not exist between t3 and another      *
  * level 0 table, e.g., t3 does not join directly with t2       *
  *  - t2 is significantly larger than both t1 and t3            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to 11.50.xC9.                                        *
  ****************************************************************
  

Problem conclusion

• The problem is fixed in 11.50.xC9.
  

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

  IBM IDS ENTRP E

• Fixed component ID

  5724L2304

Applicable component levels

• RB15 PSN

     UP