Subscribing to and Querying Topics
This section describes commands used to retrieve content messages from AMPS, including both queries and subscriptions.
For details on the differences between these commands, see the AMPS User Guide.
Command | Usage |
---|---|
| Receive a stream of messages from a topic. |
| Query a snapshot of the values within a topic in the State of the World (SOW). |
| Query a snapshot of the values within a topic in the SOW and begin a subscription atomically at the point of query. |
| Receive a stream of messages from a topic. If the topic is in the SOW, and it is possible to construct a partial message, receive only fields that have changed (fields that identify the message are also included by default). |
| Query a snapshot of the values within a topic in the SOW and begin a subscription atomically at the point of query. If the topic is in the SOW, and it is possible to construct a partial message, receive only fields that have changed (fields that identify the message are also included by default). |
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