Deterministic datasource selection was enabled in Tungsten Clustering 6.0.3.
Within composite clusters, both composite and composite multimaster, the
selection of datasources can be made to be deterministic by specifying
the list of datasources within the
configuration. The configuration is based on an ordered, comma-separated
list of services to use which are then selected in order.
The format of the speecification is as follows:
The specification operates on the following rules:
List of service names in order
If the service name has a dash prefix it is always explicitly excluded from the list of available datasources
If a datasource is not specified, it will always be picked last
For example, in a setup made of three data service,
europe using the following configuration:
app_user secret usa,asia,-europe
Will select data sources in data service
usa is not available, in
asia is not availble, then
connection will not succeed since
europe has been negated.