MapR 5.1 is at End of Life (EOL) and no longer supported. Please see the latest documentation. This documentation is not being updated.

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5.1 DB & Streams
This section covers the MapR-DB, MapR-Streams, and MapR-Gateways features. Each feature may contain both administrator and developer topics.
MapR Streams
MapR Streams brings integrated publish/subscribe messaging to the MapR Converged Data Platform.
Monitoring the Flow of Messages
The speed at which messages flow from producers to partitions and from partitions to consumers depends on the performance of your producers, cluster nodes hosting partitions, and your consumers.

MapR 5.1 Documentation

5.1 DB & Streams
This section covers the MapR-DB, MapR-Streams, and MapR-Gateways features. Each feature may contain both administrator and developer topics.
- MapR-DB
- MapR Streams
  MapR Streams brings integrated publish/subscribe messaging to the MapR Converged Data Platform.
  - MapR Streams Concepts
  - Life of a Message
    To show how the MapR Streams concepts fit together, here is an example of the flow of one message from a producer to a consumer.
  - Getting Started with MapR Streams
    If you have a basic understanding of MapR Streams's components and the typical flow of messages from producers to consumers, you can give MapR Streams a try.
  - MapR Streams in Detail
    If you understand the basics about the components of MapR Streams, the flow of messages from producers to consumers, and how producers and consumers are coded, it's time to cover them in more detail.
  - Monitoring the Flow of Messages
    The speed at which messages flow from producers to partitions and from partitions to consumers depends on the performance of your producers, cluster nodes hosting partitions, and your consumers.
    - Monitoring Producers
      To get a sense of how quickly producers are sending messages to the producer client library, you can run the command stream topic info at intervals.
    - Monitoring Cluster Nodes That Host Partitions
      You can find out which nodes in a MapR cluster are being used for topics in a stream by running the command maprcli stream topic info. The nodes are listed in the servers field.
    - Monitoring Consumers
      There are two commands that you can run at intervals to get a sense of how far behind a consumer is in a partition. The consumer must belong to a consumer group, even if the consumer is the only member of that group.
  - Replicating MapR Streams
    You can replicate streams to other MapR clusters worldwide or to other streams within a MapR cluster.
  - Querying Messages in MapR Streams
    You can develop Java applications or modify existing Java applications to query messages that are in MapR streams by using the methods in the Streams class.
  - Migrating Apache Kafka 0.9.0 Applications to MapR Streams
    There are only two steps that you need to follow to migrate applications written with the Apache Kafka 0.9.0 Java API to MapR Streams.
  - Mirroring Topics with Apache Kafka's MirrorMaker
    Use Apache Kafka's MirrorMaker utility either to mirror topics that are in Apache Kafka clusters to streams that are in MapR clusters or to Mirror topics that are in MapR clusters to Apache Kafka clusters.
  - Utilities for MapR Streams
    MapR Streams provides the following utilities.
- MapR Gateways
  A MapR gateway mediates one-way communication between a source MapR cluster and a destination cluster. MapR-DB binary tables and MapR Streams streams can be replicated.

Monitoring the Flow of Messages

The speed at which messages flow from producers to partitions and from partitions to consumers depends on the performance of your producers, cluster nodes hosting partitions, and your consumers.