Advanced Messaging and the SOW

A SOW topic is the basis for many of the advanced messaging features in AMPS. While not all of these features are discussed in detail in this introduction, many features of AMPS are made possible because AMPS can retain the current state of each unique message.

The advanced messaging features that the SOW enables include:

• Views and aggregations over topics (including joins between topics)

• Publishing incremental updates to a message (called delta publishing in AMPS)

• Receiving incremental updates to a message (called delta subscription in AMPS)

• Determining when a message no longer matches a filter (called out-of-focus notification in AMPS)

• Providing a snapshot of an update to a rapidly changing record at regular intervals, rather than providing every update (called conflation in AMPS)

These features can greatly simplify the processing an application needs to perform, making it easier to develop applications and increasing application performance. However, for a messaging system to provide these features, whenever a message arrives, the messaging system must have access to both the current message and the previous, saved state of the message. SOW topics provide that access for AMPS, and enable the advanced messaging features.