Topic Creation
Topics are created in streams and contain logical collections of messages. They can
be created either automatically through your producer application or manually through the
Control System or the maprcli
commands.
Automatic Creation
If the topic does not already exist, a topic is created automatically when a producer first publishes a message to it. This is the default behavior.For example, you created the stream anonymous_usage that you intend to use to collect data about the usage of a software application that is soon to be released. However, you did not create any stream topics because the topics were not known at the time. After the software is released to the public, at some point, a producer application starts publishing messages to a topic that is created based on the range within which the producer's IP address falls. At another point in time, another producer application starts publishing messages to a topic based on a different range of IP addresses. Eventually, the stream contains a number of topics for different IP address ranges.
autocreate
parameter to false either when creating the
stream or by editing the stream. See the maprcli
stream create or stream edit command for more information. If you
turn off automatic creation, you must manually create the stream topic, otherwise,
the publishing of a message fails.Manual Creation
To create topics manually, use either the Control System or themaprcli
commands. See Administering Streams for information about
managing HPE Ezmeral Data Fabric Streams streams, topics and replication.
See the stream topic create command for specific
information about creating stream topics with the maprcli
command.
For example, you created a stream called systemMetrics that you intend to use to collect operational metrics from systems in your enterprise. You did create several topics based on system, location, company department, project, or some other criterion. In this case, you could create topics in advance because they were pre-planned.