Configuring a SOW

The SOW section of the configuration file specifies the configuration for the AMPS State of the World (SOW). AMPS supports several different types of SOW topics that can be configured as part of the SOW.

A Topic acts as a last value cache to store data. For more information on SOW Topic last value caching, see 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 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 this 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, Queue, View, or ConflatedTopic as the underlying source of information. The Aggregation and Analytics section of this 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.

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

Described below are the configuration items available for SOW. Expand each item for more details.

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 UnderlyingTopic for views, aggregates, and conflated topics.

See the Configuring Topics in a SOW 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 Message Queues section in this guide for a full description of their functionality.

AMPS queues provide a variety of replication models.

See the Configuring Queues in a SOW section of this guide for information on configuring a Queue.

View

Defines a view over one or more SOW topics, conflated topics, or other views.

A view can perform aggregation and can JOIN multiple topics together. It can also be based on a SOW topic of one message type and project results of a different message type.

See the Configuring Views in a SOW section of this guide for information on configuring a View.

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.

See the Configuring Conflated Topics in a SOW section of this guide for information on configuring a ConflatedTopic.