DB2 configuration parameters

You can improve directory server performance by tuning the DB2® configuration parameters for the database that is associated with the directory server.

To improve the directory server performance, you can set the DB2 configuration parameters such as DBHEAP and LOGFILSIZ. To update the parameters, run the following commands:

db2 update database configuration for database_name \
using parm_name parm_value
db2 force applications all
db2stop 
db2start 

where, the variable specifies:

• database_name is the name of your database.
• parm_name is the parameter to change.
• parm_value is the value to assign the parameter.

You can also use the idsperftune tool to set the DB2 configuration parameters. To update the DB2 configuration parameter with the values in the perftune_input.conf file, run the following command:

idsperftune -I instance_name -A -u update

To retrieve DB2 configuration parameters and their values, you can use the DB2 commands. You can retrieve the DB2 parameter and their current values with the following command:

db2 get database configuration for database_name

where, database_name is the name of your database. For example, the following output shows the default settings of a directory server instance, ldapdb2:

 db2 get database configuration for ldapdb2 | egrep'HEAP|MAXLOCKS|MINCOMMIT'

 Percent. of lock lists per application       (MAXLOCKS) = AUTOMATIC(98)
 Sort heap thres for shared sorts (4KB) (SHEAPTHRES_SHR) = AUTOMATIC(273)
 Sort list heap (4KB)                         (SORTHEAP) = AUTOMATIC(54)
 Database heap (4KB)                            (DBHEAP) = AUTOMATIC(2579)
 Utilities heap size (4KB)                (UTIL_HEAP_SZ) = 85239
 SQL statement heap (4KB)                     (STMTHEAP) = AUTOMATIC(4096)
 Default application heap (4KB)             (APPLHEAPSZ) = AUTOMATIC(1280)
 Statistics heap size (4KB)               (STAT_HEAP_SZ) = AUTOMATIC(4384)
 Group commit count                          (MINCOMMIT) = 1

You must not modify the default settings of the parameters; unless you determined a value to assign for a parameter. For example, if you set MINCOMMIT to a value other than 1, you might get poor performance results. You can change the parameter values by using the following commands:

db2 update db cfg for ldapdb2 using parm_name parm_value
db2 terminate
db2 force applications all

where, parm_name is the name of the parameter. You can set a parameter that is generated from the db2 get database configuration command with a value. The parm_value variable indicates the new value to assign.

Incorrect settings for some database parameters can cause database failures. If database failure occurs, check the following files for DB2 error messages:

For IBM® Security Directory Server, version 6.0 and later

• db2instance_owner_home_directory/idsslapd-instance_name/logs/db2cli.log
• db2instance_owner_home_directory/sqllib/db2dump/db2diag.log

You can also run the following command to retrieve the DB2 configuration parameter values. The command shows the DB2 configuration parameters for the entire database instance.

db2 get database manager configuration

Changes to DB2 configuration parameters do not take effect until you restart the database with the db2stop and db2start commands.

For tuning DB2 buffer pools, you can use the DB2 utility, DB2 AUTOCONFIGURE. This DB2 utility calculates and provides the values for the DB2 buffer pools, database configuration, and database manager configuration parameters. For example, if you specify NONE with DB2 AUTOCONFIGURE , the utility returns the values that are required to be modified in the configuration but does not apply them.

db2 AUTOCONFIGURE USINGMEM_PERCENT 60 WORKLOAD_TYPE simpleNUM_STMTS 500
ADMIN_PRIORITY performanceIS_POPULATED YESNUM_LOCAL_APPS 20NUM_REMOTE_APPS 20
ISOLATION RRBP_RESIZEABLE YES APPLY NONE

The DB2 AUTOCONFIGURE utility with the DB AND DBM parameter returns and applies the changes to the buffer pool settings, database manager configuration, and the database configuration.

db2 AUTOCONFIGURE USINGMEM_PERCENT 60WORKLOAD_TYPE simpleNUM_STMTS 500
ADMIN_PRIORITY performanceIS_POPULATED YESNUM_LOCAL_APPS 20NUM_REMOTE_APPS 20
ISOLATION RRBP_RESIZEABLE YES APPLY DB AND DBM

For more information, search DB2 AUTOCONFIGURE in the IBM DB2 documentation at http://pic.dhe.ibm.com/infocenter/db2luw/v9r7/index.jsp.

For a list of DB2 parameters that affect database performance, visit the IBM DB2, version 9.7 documentation website at http://publib.boulder.ibm.com/infocenter/db2luw/v9r7/index.jsp.