Abstract: A system of publishing data from a data repository server to a subscribing client, wherein a subscribing selector server receives data published by the data repository server, filters the published data in accordance with filtering criteria defined on the selector server, and re-publishes the filtered data to the subscribing client, and wherein the filtered data is cached on the selector server and is available for querying by the subscribing client. A number of analytical engines are provided and a broker framework receives requests for an analysis of data and selects one or more engines to use in carrying out the requested analysis. Checkpoints are used to ensure consistency of data.