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Segment Metadata Queries

Segment metadata queries return per segment information about:

Cardinality of all columns in the segment
Estimated byte size for the segment columns in TSV format
Interval the segment covers
Column type of all the columns in the segment
Estimated total segment byte size in TSV format
Segment id

{
  "queryType":"segmentMetadata",
  "dataSource":"sample_datasource",
  "intervals":["2013-01-01/2014-01-01"]
}

There are several main parts to a segment metadata query:

property	description	required?
queryType	This String should always be "segmentMetadata"; this is the first thing Druid looks at to figure out how to interpret the query	yes
dataSource	A String defining the data source to query, very similar to a table in a relational database	yes
intervals	A JSON Object representing ISO-8601 Intervals. This defines the time ranges to run the query over.	yes
merge	Merge all individual segment metadata results into a single result	no
context	An additional JSON Object which can be used to specify certain flags.	no

The format of the result is:

[ {
  "id" : "some_id",
  "intervals" : [ "2013-05-13T00:00:00.000Z/2013-05-14T00:00:00.000Z" ],
  "columns" : {
    "__time" : { "type" : "LONG", "size" : 407240380, "cardinality" : null },
    "dim1" : { "type" : "STRING", "size" : 100000, "cardinality" : 1944 },
    "dim2" : { "type" : "STRING", "size" : 100000, "cardinality" : 1504 },
    "metric1" : { "type" : "FLOAT", "size" : 100000, "cardinality" : null }
  },
  "size" : 300000
} ]

1.6 KiB Raw Blame History

Segment Metadata Queries

1.6 KiB

Raw Blame History