IT05033: COGNOS QUERY WITH NESTED SELECTS AND LEFT OUTER JOINS CRASHES THE ENGINE

APAR status

• Closed as program error.

Error description

• A complex query (typically originated by Cognos) consisting of
  ansi joins and nested selects results in multiple assert
  failures and eventually crashes the engine.
  
  The most common assert failure which usually comes first has
  failure stack similar to the one below:
  afstack
  afhandler
  afcrash_interface
  mt_lock
  sapi_drain_mem
  sapi_destroy_mem
  relsdbmem
  doreleasesdb
  sqcmd
  sq_cmnd
  sq_prepare
  sqmain
  spawn_thread
  th_init_initgls
  startup
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of 12.10.xC4.                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * A complex query may result in server crash under the         *
  * following conditions:                                        *
  *   - main query has one view (e.g. view1) or derived table    *
  * that has UNION ALL in it, this view is folded                *
  *   - main query has another view (e.g. view2) or derived      *
  * table that has UNION ALL in it, this view is materialized    *
  * (e.g, used as subservient table in outer join)               *
  *   - the definition of the materialized view (view2 above)    *
  * has in its definition a nested view(e.g. view3) or derived   *
  * table, which is also materialized                            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Update to IDS-12.10.xC5                                      *
  ****************************************************************
  

Problem conclusion

• Problem Fixed In IDS-12.10.xC5
  

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

• RC10 PSN

     UP