MDAC 2.5 SDK - ODBC Data Source Administrator

Setting ODBC Connection Pooling Options

Connection pooling enables an application to use a connection from a pool of connections that do not need to be reestablished for each use. You can use the Connection Pooling tab of the ODBC Data Source Administrator dialog box to alter the connection Retry Wait time for any selected driver. You can also use it to enable and disable performance monitoring. Double-click a driver name to set the connection time-out period.

At the driver level, connection pooling is enabled by the CPTimeout registry value. This selective per-driver enabling allows a system administrator to enable connection pooling for just the drivers that can support it. It is accomplished by setting the default value of CPTimeout during the driver's setup program.

When the ODBC Driver Manager detects that a database server is unavailable, it waits for a certain amount of time before attempting to reconnect. You can adjust the waiting time by setting the Retry Wait time value (in seconds) in the Connection Pooling tab of the ODBC Data Source Administrator dialog box. Double-click a driver name to set the connection time-out period.

For more information about connection pooling, see ODBC Connection Pooling in Chapter 6 of the ODBC Programmer's Reference, "Connecting to a Data Source or Driver."

Performance Monitoring

Performance monitoring tracks connection performance by recording a variety of statistics. These statistics can be customized by the developer to include items such as the following:

• The number of connections made to data sources per second.
  
  
• The number of disconnections made from data sources per second.
  
  
• The number of connections to the pool per second.
  
  
• The number of disconnections from the pool per second.
  
  
• Connections currently active.
  
  
• The current number of connections being used by applications.
  
  
• Connections currently free.
  
  
• The current number of connections available for connection requests.

You must specify your own monitoring parameters. Samples for performance monitoring have been included with this version of ODBC.