Database connections for coordinated message flows

When you configure a message flow to access a database, the broker establishes a connection to that database based on the ODBC DSN. To coordinate the database updates with other updates (determined by the configuration you have set for each node that accesses a database), the broker makes a connection for each transaction mode for each DSN accessed on each message flow thread.

Therefore if you set the Transaction Mode property for one node in the message flow to Automatic and for another node to Commit, the broker establishes two separate connections to this DSN from the same thread. Take this into account when you calculate the number of connections required between a broker and a specific DSN.

For further information about connections made by the broker to user databases, see User database connections.

Connections to user databases are in addition to the runtime connections that are required by the broker (to the DB2, Oracle, Sybase, or SQL Server database that is defined to hold its internal information). For details of these connections, refer to Connecting to the databases.

Related concepts
Message flows overview
Related tasks
Connecting to the databases
Configuring coordinated message flows
Creating a message flow
Defining message flow content
Related reference
User database connections
Built-in nodes