37. Glossary of AMPS TerminologyΒΆ
Term | Definition |
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Acknowledgment | A networking technique in which the receiver of a message is responsible for informing the sender that the message was received. In AMPS:
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Authentication | The process of establishing a proven identity for a connection to AMPS. |
Conflation | The process of merging a group of messages into a single message. For example, when a particular record in the SOW is updated hundreds or thousands of times a second, conflation can enable an application to receive the most recent update every 300ms, reducing the network traffic to the application while still guaranteeing that the application has recent data. |
Conflated Topic | A copy of a SOW topic that conflates updates on a specified interval. This helps to conserve bandwidth and processing resources for subscribers to the conflated topic. |
Delta | A message that contains only the differences between the previous state of a stored message and the new state of the stored message. AMPS supports delta messaging for both publish (changing a subset of fields in a message) and subscribe (receiving only the fields of a message that have changed). |
Entitlement | The process of assigning permissions to a connection based on the identity established for that connection. |
Expression | A text string that produces a specific value. AMPS uses expressions in filters and when constructing fields for enrichment or projecting views. |
Filter | A text string that is used to match a subset of messages from a larger set of messages. In AMPS, every filter is an AMPS expression that returns TRUE or FALSE. |
Message Expiration | The process where the lifespan of records stored is limited. |
Message Type | The data format used to encapsulate messages. Each message within AMPS has a single, defined message type. Each connection to AMPS uses a single, defined message type. |
OOF (Out of Focus) | Notification to a subscriber that a message which was previously a result of a SOW or a SOW subscribe filter result has either expired, been deleted from the SOW or has been updated such that it no longer matches the filter criteria. |
Replication | The process of duplicating the messages stored into an AMPS instance to one or more additional AMPS instances. |
Replication Destination | An instance of AMPS that is receiving messages directly from another AMPS instance (the replication source). |
Replication Source | An instance of AMPS which receives a published message from an application, and then sends the message directly to one or more other AMPS instances (the replication destinations). |
Slow Client | A client that is being sent messages at a rate which is faster than it can consume, to the point where AMPS detects that the network buffer to the client has filled. |
SOW (State of the World) | The last value cache used to store the current state of messages belonging to a topic. |
SOW Key | A value used to identify a unique message in AMPS. For a given topic, you can configure AMPS to generate the SOW key based on content in the message, provide the SOW key on each message published or use a SOW key generator module to programmatically create the SOW key. |
Topic | A label which is affixed to every message by a publisher which is used to aggregate and group messages. |
Transport | The protocols used to transfer messages between AMPS subscribers, publishers and replication destinations. |
Transaction Log | A history of all messages published which can be used to recreate an up to date state of all messages processed. Applications can query and replay messages from the transaction log. |
View | A topic constructed by AMPS from the contents of one or more SOW topics. A view can aggregate or transform the underlying topics and can be of a different message format than the underlying topics. |