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

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
  - Architecture of MapR-DB
    MapR-DB's architecture gives it a large of advantages over other NoSQL databases.
  - Performance Enhancements for SSD Based MapR-DB Deployments
  - MapR-DB as a Document Database
    MapR-DB supports OJAI documents as a native data store. OJAI documents are stored in a compact binary format, not as plain ASCII text.
  - MapR-DB as a Wide-Column Database
    - Logical Model of MapR-DB Binary Tables
    - Filesystem Operations on MapR-DB Tables
    - Migrating Between Apache HBase Tables and MapR-DB Binary Tables
    - Designing Row Keys for MapR-DB Binary Tables
      A row key identifies a row in a MapR-DB binary table.
    - Designing Column Families for MapR-DB Binary Tables
      Scanning an entire table for matches can be very performance-intensive. Column families enable you to group related sets of data and restrict queries to a defined subset, leading to better performance. When you design a column family, think about what kinds of queries are going to be used the most often, and group your columns accordingly.
    - Configuring Maximum Row Sizes for Binary Tables
      The default maximum row size at installation is 32MB. You can configure this maximum by changing the value of the mfs.db.max.rowsize.kb parameter with the maprcli config save command.
    - Enabling Access to MapR Tables via HBase APIs, hbase shell, and MapReduce Jobs
    - Creating MapR-DB Binary Tables
    - Displaying Table Region Information for MapR-DB Tables
    - Creating Applications That Access MapR-DB Binary Tables
    - Bulk Loading and MapR-DB Binary Tables
    - Replicating MapR-DB Binary Tables
    - Indexing MapR-DB Binary Tables with Elasticsearch
      - Uses of Indexing MapR-DB Binary Tables with Elasticsearch
      - Elasticsearch entities
      - Registering Elasticsearch Clusters with MapR Clusters
        To register an Elasticsearch cluster with a MapR cluster, you run a script that copies the Elasticsearch cluster’s configuration file (elasticsearch.yml), JAR files, and plugin JAR files into MapR-FS on the MapR cluster where you run the script from. When you run the script, you provide the IP address or hostname of the Elasticsearch node to copy the files from.
      - Configuring Replication to Elasticsearch Types
        When you index a MapR-DB binary table, you set up replication from that table to a type in an Elasticsearch cluster. After an initial load of data from the source table into the type, updates to the source table are replicated immediately to the type. Updates are not replicated in batches but as they happen. Replication of data to Elasticsearch indexes is asynchronous. MapR-DB does not wait to receive confirmation that changes have been replicated before it notifies client applications that requested operations on the MapR-DB database are complete.
      - Mapping MapR-DB Data to Elasticsearch Data Types Other Than String
        Converting Data to Elasticsearch Data Types that MapR-DB Supports
        If you want to convert source data (which is stored as byte arrays) to Elasticsearch types that MapR-DB supports, you can create each destination index explicitly with Elasticsearch’s create index API and then define the mapping of data types with Elasticsearch’s put mapping API. MapR gateways perform the data conversion.
        Converting Data to Elasticsearch Data Types That MapR-DB Does Not Support
        If you want to convert your source data into an unsupported Elasticsearch data type, write Java routines to tell MapR-DB how to perform conversions.
      - Tuning the Performance of Data Indexing
    - Impersonation via the HBase REST Gateway
- MapR Streams
  MapR Streams brings integrated publish/subscribe messaging to the MapR Converged Data Platform.
- 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.

Mapping MapR-DB Data to Elasticsearch Data Types Other Than String

Data in MapR-DB binary tables is stored as byte arrays. When data is replicated to an index in Elasticsearch, the gateways can convert your source data to Elasticsearch data types in three different ways.

By default, MapR-DB assumes that source data is UTF-8 encoded, and gateways convert the source data to strings. If you use this default conversion, you do not have to create destination indexes with the Elasticsearch API before loading them and replicating to them. However, your applications might require your data to be in other data types.

Instead of this default conversion, you can use two different methods of converting data to Elasticsearch data types.

WARNING: If you use the default conversion of source MapR-DB data to strings, ensure that automatic date-type detection and automatic numeric-type detection are disabled in your Elasticsearch cluster. Otherwise, Elasticsearch might detect data types in the strings and subsequently expect those data types in your data, not strings. Because you would not have set up conversion of your source data to other data types, MapR gateways would continue to send strings to Elasticsearch, which would then throw an error and stop indexing.