DB2 FOR LUW / DB2FORLUW / A50 - DB2

With DB_MEM_THRESH 100 setting (the new default on version 
10.5), all the memory released by freeing bufferpool memory is 
cached.  The structures used to track the freed memory build up, 
resulting in longer and longer traversal time as more memory is 
freed. 
 
For example, deactivating a database with 100GB of bufferpool 
may take 15 minutes.

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* USERS AFFECTED:                                              * 
* Large DB2 / Windows systems are vulnerable                   * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 10.5 Fix Pack 7                       * 
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db2 update db cfg for <database> using db_mem_thresh 10 
 
This can be done dynamically after connecting to the database. 
For a quicker database deactivation, it is only important that 
the "10" setting is in place prior to database deactivation (or 
last connection terminates if the database is not explicitly 
activated)  If the default "100" is desired for normal 
operations, it can be set any time before the next activation or 
online (over a connection) after the database next activates. 
 
For extremely large configurations (eg. bufferpools > 100GB), it 
may be necessary to increase the bufferpool allocation size to 
1MB, which will bypass most of the overhead. 
 
   db2set DB2_ALLOCATION_SIZE=1MB 
 
This setting is only effective as of the next instance 
activation (db2start).  This is an deprecated registry setting 
and should only be used as a workaround for this APAR.  Once the 
Fix Pack containing this APAR is applied, this setting should be 
removed.

Problem first fixed in DB2 Version 10.5 Fix Pack 7

See Local Fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

02.03.2015
18.02.2016
18.02.2016