IT29344: MEMORY CORRUPTION / TRAP IN ALLOCMEM TERMFASTALLOC DURING COLUMNAR DATA PROCESSING

APAR status

• Closed as program error.

Error description

• During re-execution of a statement processing columnar data, a
  cached invalid pointer is accessed resulting in memory
  corruption.  The overwritten memory is often memory allocation
  metadata, resulting in traps while allocating or freeing memory.
  
  Trapping functions may vary widely, but the most common
  functions are :
  allocMem / sqloFastThreadAllocator::allocMem
  termFastAlloc / sqloFastThreadAllocator::termFastAlloc
  

Local fix

• db2set -im DB2_REDUCED_OPTIMIZATION="COL_IXSCAN_ALL_V1133 OFF"
  db2 connect to <database>
  db2 flush package cache dynamic
  - the "flush" is required to invalidate vulnerable cached SQL
  execution plans
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * ALL                                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Db2 11.1 Mod 4 Fixpack 5 or higher                *
  ****************************************************************
  

Problem conclusion

• First fixed in Db2 11.1 Mod 4 Fixpack 5
  

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

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSN

     UP