IT28161: HASH JOIN EXECUTION SHOULD BE AVOIDED IF EITHER BUILD OR PROBE SIDE ALREADY KNOWN TO BE EMPTY

APAR status

• Closed as program error.

Error description

• An expensive (non-outer) hash join, once chosen by the query
  optimizer, seems to get executed even in cases where a zero-rows
  outcome already can be predicted by either the build or the
  probe side having no rows.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of IDS prior to 12.10.xC13.                            *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * An expensive (non-outer) hash join, once chosen by the query *
  * optimizer, seems to get executed even in cases where a       *
  * zero-rows outcome already can be predicted by either the     *
  * build or the probe side having no rows.                      *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  

Problem conclusion

• Fixed in IDS 12.10.xC13.
  

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

  INFORMIX SERVER

• Fixed component ID

  5725A3900

Applicable component levels