State of the World (SOW)

The SOW section of the configuration file holds the configuration for the AMPS State of the World (SOW).

There are several different types of topics that are configured as part of the State of the World.

More information on SOW Topic last value caching is available in the AMPS User Guide in the sections on State of the World (SOW) Topics, Querying the State of the World (SOW), Out of Focus Messages, State of the World Message Enrichment, Incremental Message Updates, and Receiving Only Updated Fields.

A ConflatedTopic is a way to mitigate message velocities that are too high for subscribers to efficiently process. A ConflatedTopic provides a way for those subscribers to consume data from a Topic, View, or another ConflatedTopic. A conflated topic also supports queries and subscriptions as described in Querying the State of the World (SOW), Out of Focus Messages, and Receiving Only Updated Fields.

A Queue, LocalQueue, or GroupLocalQueue provides a mechanism for ensuring that messages are processed by an application once, as described in the Message Queues section of the AMPS User Guide. The differences between the queue types specify how the queue will behave in a replicated set of instances, as described in Queue Replication Types. The current state of messages that have not been delivered to applications can be queried as described in Querying the State of the World (SOW).

View topics are configured using one or more of Topic, View, ConflatedTopic, or Queue as the underlying source of information. The Aggregation and Analytics section of the AMPS User Guide describes how to configure a view. A view also supports queries and subscriptions as described in Querying the State of the World (SOW), Out of Focus Messages, and Receiving Only Updated Fields.

Element	Description
Topic	Specifies that AMPS will record distinct messages for this topic in the SOW. SOW topic definitions are used directly as a last-value cache, and are required for many of the advanced messaging features in AMPS such as out-of-focus notifications and delta messaging. SOW topic definitions can also be used as the underlying topics for views, aggregates, and conflated topics. See the SOW/Topic section of this guide for information on configuring a Topic.
Queue	Defines a message queue. Rather than delivering each message to all matching subscriptions, message queues provide features to help ensure that each message is delivered to and processed by a single subscriber. See the AMPS User Guide for a full description of the functionality of message queues. AMPS queues provide a variety of replication models. See the SOW/*Queue section of this guide for information on configuring queues.
View	Defines a view over one or more SOW topics, conflated topics, or other views. A view can perform aggregation, can JOIN multiple topics together. A view can be based on a SOW topic of one message type and project results of a different message type. View configuration is described in the SOW/View section of this guide.
ConflatedTopic	Defines a copy of a SOW topic or view that receives current value updates at a specified interval, conflating any changes to values that occur between the scheduled updates. ConflatedTopic configuration is described in the SOW/ConflatedTopic section of this guide.

The elements within the SOW section are described in detail in the following sections.