Database service configuration tips

Use these tips to configure your database services for optimal database services performance.

Do not change the default settings of db_maxConnection_module_Name_system for all services.
The total number of maximum connections that are used in all services must be less than the total number of database connections set for a given database. The following formula calculates the total maximum number of database connections of an IBM® Product Master deployment:
```
db_maxConnection_admin + ( db_maxConnection_appsvr * A ) + 
( db_maxConnection_scheduler * S ) + db_maxConnection_eventprocessor + 
db_maxConnection_workflowengine
```
Where, A is the number of application server instances and S is the number of scheduler instances.
Administrators are advised to adjust the db_maxConnection_module_Name and db_maxConnection_module_Name_default parameters whenever the number of concurrent users increases. The following formula calculates the required value for db_maxConnection_module_Name for a given number of concurrent users:
```
db_maxConnection_MODULE = U * (1.5)
```
Where, U is the number of concurrent users.
For eventprocessor and queuemanager the following formula calculates the value of db_maxConnection_module_Name_default:
```
db_maxConnection_MODULE_default = db_maxConnection_MODULE - db_maxConnection_MODULE_system 
```
For appsvr, scheduler, workflowengine and messaging the following formula calculates the value of db_maxConnection_module_Name_default:
```
db_maxConnection_MODULE_default = db_maxConnection_MODULE - db_maxConnection_MODULE_system - 
db_maxConnection_MODULE_gdsmsg
```

Database connections and the number of threads can be configured for each module

The following details list how the number of database connections and the number of threads can be configured for each module. It also gives you some guidelines how these numbers should relate to each other. This ratio or formula differs for the different modules.

admin module: To modify the number of database connections: In the common.properties file, you can use the db_maxConnection_admin parameter with the default value set to 5.; For example: db_maxConnection_admin=5.; For more information, see Database parameters for the Admin module section in the common.properties file parameters file.; To modify the number of threads: Cannot be influenced because this is a single thread.; How the number of database connections should relate to the number of threads: Not applicable because this is a single thread.
application server module: To modify the number of database connections: In the common.properties file, you can use the db_maxConnection_appsvr parameter with the default value set to 30.; For example: db_maxConnection_appsvr=30.
For more information, see the Database parameters for the Application server module section in the common.properties file parameters file.; To modify the number of threads: The number of threads can be influenced through the threadpool settings of your application server.
For more information, see Thread pool settings.; How the number of database connections should relate to the number of threads: One thread might have at most zero or more database connections.
eventprocessor module: To modify the number of database connections: In the common.properties file, you can use the db_maxConnection_eventprocessor parameter with the default value set to 6.; For example: db_maxConnection_eventprocessor=6.
For more information, see the Database parameters for the Event processor module section in the common.properties file parameters file.; To modify the number of threads: Cannot be influenced because this is a single thread.; How the number of database connections should relate to the number of threads: Not applicable because this is a single thread.
gdsmsg module: To modify the number of database connections: In the common.properties file, you can use the gdsmsg parameter to change the maximum connections parameter with the default value set to 30. For example: db_maxConnection_appsvr_gdsmsg=10.
For more information, see the Database parameters for the GDS messaging module section in the common.properties file parameters file.; To modify the number of threads: In the common.properties file, you can change the maximum connections parameter with the default value set to 30.; For example: db_maxConnection_appsvr_gdsmsg=10.; How the number of database connections should relate to the number of threads: One thread might have at most zero or more database connections.
scheduler module: To modify the number of database connections: In the common.properties file, you can use the db_maxConnection_scheduler parameter with the default value set to 70.; For example: db_maxConnection_scheduler=70.
For more information, see Database parameters for the Entry processor parameters section in the common.properties file parameters file.; To modify the number of threads: In the common.properties file, you can use the num_threads parameter with the default value set to 8. For example: num_threads=8.
For more information, see the num_threads property in the common.properties file parameters file.; How the number of database connections should relate to the number of threads: One thread might have at most zero or more database connections.
queuemanager module: To modify the number of database connections: In the common.properties file, you can use the db_maxConnection_queuemanager parameter with the default value set to 12.; For example, db_maxConnection_queuemanager=12.
For more information, see Database parameters for the Queue manager module section in the common.properties file parameters file.; To modify the number of threads: In the common.properties file, you can use the queuemanager_num_threads parameter with the default value set to 10. For example: queuemanager_num_threads=10.
For more information, see the queuemanager_num_threads property in the common.properties file parameters file.; How the number of database connections should relate to the number of threads: One thread might have at most zero or more database connections.
workflow engine module: To modify the number of database connections: In the common.properties file, you can use the db_maxConnection_workflowengine parameter with the default value set to 70.; For example: db_maxConnection_workflowengine=70.
For more information, see the Database parameters for the Workflow engine module section in the common.properties file parameters file.; To modify the number of threads: In the common.properties file, you can use the wfe_num_threads parameter with the default value set to 8. For example: wfe_num_threads=8.
For more information, see the wfe_num_threads property in the common.properties file parameters file.; How the number of database connections should relate to the number of threads: One thread might have at most zero or more database connections.