IT21211: SLOW DATABASE ACTIVATION, CREATE/ALTER BUFFERPOOL, LOAD OPERATIONS ON LARGE WINDOWS SYSTEMS

Db2 Version 11.1 Mod 3 Fix Pack 3 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix001 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix002 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 5 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 7 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• On Windows, allocating memory may be
  significantly slower for databases with larger memory footprints
  ( many GBs ).  Because DB2's memory allocations on Windows are
  typically small and incremental, coalesce checks end up being
  performed on a very large number of OS allocations.  Activities
  which are intense in terms of allocating memory (such as
  bufferpool activation, creation, or increase, or initializing
  LOAD operations), may suffer some degradation as a result
  
  The call stack will contain the following :
  SMemSet::checkRecommitable
  SMemSet::recommitChunksUntilTargetReached
  SMemSet::getChunksFromTree
  SMemSet::getContiguousChunks
  SMemBasePool::getNewChunkSubgroup
  

Local fix

• Consider using
     db2set DB2MEMDISCLAIM=NO
  followed by db2stop; db2start, which avoids the need for any
  coalesce check.
  
  Note that DB2MEMDISCLAIM=NO disables STMM-tuning of
  database_memory, though STMM will still tune the main consumers
  (bufferpools, locklist, package cache, shared sort) inside the
  existing database_memory size.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Larger Windows systems                                       *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to DB2 Version 11.1 Mod 3 Fix Pack 3                 *
  ****************************************************************
  

Problem conclusion

• Problem first fixed in DB2 Version 11.1 Mod 3 Fix pack 3
  

Temporary fix

• see Local Fix
  

Comments

APAR Information

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

  IT21209

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

Modules/Macros

• sqo
  

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSN

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