StreamBase Chronicle is an optional high-capacity event-store that can be used to provide persistent data storage in association with streaming applications. When using a Chronicle Connection component, a StreamBase application can query a Chronicle data source. The resulting data can then be processed by other components and merged with tuples from the application's input stream. This topic explains how to use an external Chronicle data source with your StreamBase application.

A Chronicle database might be installed on one or more machines, separately from the StreamBase installation. After installing and configuring the Chronicle database you want to use, you can identify it as a data source in your StreamBase application's sbd.sbconf file.

In a StreamBase EventFlow, you add a Chronicle Connection data construct that points to the Chronicle data source, and then connect the data construct to one or more Query operators, where you can perform query operations against the data source.

The following figure depicts the components in a simple EventFlow application connected to a Chronicle Database:

In StreamSQL applications, the APPLY CHRONICLE statement references the name of a Chronicle data source, and contains a SELECT clause that performs the query. In both types of applications, the query must be in the format recognized by the Chronicle database you are using, not StreamSQL statements. Here is a simple example within a StreamSQL application:

CREATE INPUT STREAM in (symbol string(4));
CREATE OUTPUT STREAM out;

APPLY CHRONICLE myChronicleDB "SELECT sum(column_name_1) 
  FROM chronicleDB_table WHERE column_name_2={symbol}" FROM in INTO out;