Terms you need to understand

Here we introduce the most important terms we use and explain what they mean in the context of OAG.

Term	Explanation
Downstream System	Any system or application that is called (forwarded to) by OAG. Often services and applications implementing business logic.
Upstream System	Callers (initiating requests) of OAG. Often also known as clients.
Logging	Writing information about the inner workings (state) of OAG to a file or other destination.
Tracing	The goal of tracing is to following a flow of activity and data processing (often known as request) through one or more systems/applications involved.
Log correlation / Correlation logging	The ability to assign log statements to a flow effectively enabling tracing. Usually log correlation is implemented by means of assigning a unique id to each flow and writing this unique id out with every log statement.