KB43101: What is the Database Instance feature “Restrict each Database Connection to one warehouse query at a time”?

Starting in Strategy 2021 Update 2, the Restrict each Database Connection to one warehouse query at a time option has been retired because concurrent SQL queries can be supported by IBM Db2 for Z/OS. You will no longer see this option when creating new connections from Strategy Developer. See KB484512 to learn about secure text input through parameterized queries. 
In Strategy versions 9.x, you can set a feature to force each database connection to point to a different Data Source Name (DSN), and each DSN point to a different physical database.
This feature is intended to be used only in certain databases such as IBM DB2/MVS (OS/390), which may not adequately support SQL query concurrency.
Follow the steps below in order to enable this feature:

• Launch Strategy Developer, connect to a project source in two or three tiers, expand the Administration menu > Configuration Managers > Database Instances.
• Right-click one the name of the database instance > Edit to open the Database Instances editor.
• in the General tab, select the Restrict each Database Connection to one warehouse query at a time checkbox, as shown below:
  

• Select the desired database connections in the Database connection (default) box.
• Click OK to save the changes and close the Database Instances editor.