Installation and Upgrade > Upgrade Guide > The Windchill Upgrade Procedure > Using the Upgrade Manager > Parallel Execution of Upgrade Database Schema
  
Parallel Execution of Upgrade Database Schema
The default value for allowable open database connections can be modified to improve upgrade performance for larger systems.
Contact your DBA to acquire the correct number of database connections available for use. In a windchill shell, from <WT_Home> directory, use the xconfmanager to update the wt.pom.maxDbConnections property in the db.properties file to the desired value. For example:
xconfmanager -t db/db.properties -s wt.pom.maxDbConnections=<desired value> -p
Additionally, the property com.ptc.windchill.upgrade.phases.upgradeschema.threadPoolSize can be used to set a limit for the number of database connections, regardless of the number of available connections, in order to reduce the possible risk that having too many threads can cause performance degradation. For example, if the number of available connections is greater than the value specified in the threadPoolSize property, the value in the threadPoolSize is used for database connections. In a windchill shell, from <WT_Home> directory, use the xconfmanager to update the threadPoolSize property in the db.properties file to the desired value. For example:
xconfmanager -t db/db.properties -s
com.ptc.windchill.upgrade.phases.upgradeschema.threadPoolSize=<desired value> -p