Develop:Journal

Persistent Message Queue: Journal

This is a new core feature, the "journal" is a custom messaging system with optional persistence. It supports efficient publish/subscribe and queries. Currently supported storage backends are PostgreSQL 9.3+ and MongoDB.

Concepts

• Messages are simple records with an ID, Timestamp, a Topic and arbitrary Payload data.
• Persistence is optional, but it allows to query stored messages.
• Indexes over payload data can be created to speed up queries.