DSConfig

System scope only

This configuration variable allows you to modify some Tango data source parameters which may be required to tune database performance on an individual basis. These parameters include whether the data source driver is thread-safe, and the maximum number of connections allowed to the data source.

DSConfig contains an array, and is not specified within the Tango 3 Server Preferences (Mac OS) or t3server.ini (Windows and UNIX) file. The contents of the DSConfig array are written to and read from a file.

For more information on the format and location of this file, see “DSConfigFile”.

By default, this file is called Data Source Preferences (Mac OS) or dsConfig.ini (Windows and UNIX). You can also set the name and location of the file to something other than the default by modifying the value of the DSConfigFile configuration variable.

It is recommended that you use the config.taf application file to modify the values of this variable.

Caution: Do not edit the dsConfig.ini file directly when Tango Server is running. Either stop Tango Server and edit this file, or use the config.taf file or your own application files to create or modify the DSConfig array, which is then automatically written out to the dsConfig.ini file.

When DSConfig is updated, changes are written immediately to the file specified by DSConfigFile. For more information on the structure of the data source configuration file, see “DSConfigFile”.

The DSConfig array has the following structure:

The type parameter defines the type of data source: ODBC, Oracle or DAM. The name parameter defines the name of the data source, the Oracle alias or connect string, or the DAM host name.

The maxconnections parameter defines the maximum number of connections that Tango Server makes to the datasource. The default is ‘0’ (no limit).

Setting maxconnections to a value other than zero can be useful if you have a limited user license for your database server. For example, if you have a five-user license only, Tango Server may use all of the connections when running application files. Setting the maxconnections value to less than five allows other users to connect to the database while Tango Server is also running. However, you should not set maxconnections to a value which is too low for your data source setup; for example, if maxconnections is set to “2” and Tango Server has two open database connections, the next user that tries to connect via Tango Server to a database may experience a wait until the connection is free, or the query may time out when the queryTimeout value is reached.

The singlethreaded parameter allows you to override what the data source tells Tango about its thread safety. If you suspect your driver is not thread-safe; that is, cannot be run in a multi-threaded configuration with no ill effects, you can set this parameter to “1” (true), which means that Tango Server only allows one thread to use the driver at any time.

If multiple data sources are using the same driver, which you want to set as singlethreaded, you must specify singlethreaded for each data source.