MapR DB JSON
The MapR DB JSON origin reads JSON documents from MapR DB JSON tables. The origin converts each document into a record.
MapR is now HPE Ezmeral Data Fabric. At times, this documentation uses "MapR" to refer to both MapR and HPE Ezmeral Data Fabric. For information about supported versions, see Supported Systems and Versions.
MapR DB JSON tables are tables in which every row is a JSON document. Each JSON document has a unique identifier stored in the _id field, which in turn is used as the row key to uniquely identify each row in the table.
When you configure the origin, you define the JSON table to read from. The origin uses the _id field in each JSON document as the offset field. You can optionally define the initial offset value to start reading from.
When the pipeline stops, the MapR DB JSON origin notes where it stops reading. When the pipeline starts again, the origin continues processing from where it stopped by default. You can reset the origin to process all available data.
Before you use any MapR stage in a pipeline, you must perform additional steps to enable Data Collector to process MapR data. For more information, see MapR Prerequisites.
Handling the _id Field
When the origin converts a JSON document into a record, it includes the _id field of the JSON document in the record. If needed, you can use the Field Remover processor in the pipeline to remove the _id field.
The _id field in a JSON document can contain string or binary data. The MapR DB JSON origin can read from JSON tables that include _id fields with one of the valid types. For example, the origin can read from a JSON table when all documents in the table have a string _id field or when all documents have a binary _id field. The origin cannot read from a table with a combination of types for the _id field.
When a JSON document contains a string _id field, the origin creates the _id field in the record as a String.
When a JSON document contains a binary _id field, the origin converts the data to String and then includes the field in the record.
Configuring a MapR DB JSON Origin
Configure a MapR DB JSON origin to read JSON documents from MapR DB JSON tables.