druid/docs/content/development/extensions-contrib/orc.md

layout	title
doc_page	ORC

ORC

To use this extension, make sure to include druid-orc-extensions.

This extension enables Druid to ingest and understand the Apache ORC data format offline.

ORC Hadoop Parser

This is for batch ingestion using the HadoopDruidIndexer. The inputFormat of inputSpec in ioConfig must be set to "org.apache.hadoop.hive.ql.io.orc.OrcNewInputFormat".

Field	Type	Description	Required
type	String	This should say orc	yes
parseSpec	JSON Object	Specifies the timestamp and dimensions of the data. Any parse spec that extends ParseSpec is possible but only their TimestampSpec and DimensionsSpec are used.	yes
typeString	String	String representation of ORC struct type info. If not specified, auto constructed from parseSpec but all metric columns are dropped	no
mapFieldNameFormat	String	String format for resolving the flatten map fields. Default is <PARENT>_<CHILD>.	no

For example of typeString, string column col1 and array of string column col2 is represented by "struct<col1:string,col2:array<string>>".

Currently, it only supports java primitive types, array of java primitive types and map of java primitive types. Thus, compound types 'list' and 'map' in ORC types are supported. Note that, list of list is not supported, nor map of compound types. For map types, values will be exploded to several columns where column names will be resolved via mapFieldNameFormat.

For example of hadoop indexing:

{
  "type": "index_hadoop",
  "spec": {
    "ioConfig": {
      "type": "hadoop",
      "inputSpec": {
        "type": "static",
        "inputFormat": "org.apache.hadoop.hive.ql.io.orc.OrcNewInputFormat",
        "paths": "/data/path/in/HDFS/"
      },
      "metadataUpdateSpec": {
        "type": "postgresql",
        "connectURI": "jdbc:postgresql://localhost/druid",
        "user" : "druid",
        "password" : "asdf",
        "segmentTable": "druid_segments"
      },
      "segmentOutputPath": "tmp/segments"
    },
    "dataSchema": {
      "dataSource": "no_metrics",
      "parser": {
        "type": "orc",
        "parseSpec": {
          "format": "timeAndDims",
          "timestampSpec": {
            "column": "time",
            "format": "auto"
          },
          "dimensionsSpec": {
            "dimensions": [
              "name"
            ],
            "dimensionExclusions": [],
            "spatialDimensions": []
          }
        },
        "typeString": "struct<time:string,name:string>",
        "mapFieldNameFormat": "<PARENT>_<CHILD>"
      },
      "metricsSpec": [{
        "type": "count",
        "name": "count"
      }],
      "granularitySpec": {
        "type": "uniform",
        "segmentGranularity": "DAY",
        "queryGranularity": "ALL",
        "intervals": ["2015-12-31/2016-01-02"]
      }
    },
    "tuningConfig": {
      "type": "hadoop",
      "workingPath": "tmp/working_path",
      "partitionsSpec": {
        "targetPartitionSize": 5000000
      },
      "jobProperties" : {},
      "leaveIntermediate": true
    }
  }
}

Almost all the fields listed above are required, including inputFormat, metadataUpdateSpec(type, connectURI, user, password, segmentTable). Set jobProperties to make hdfs path timezone unrelated.