DatasourceMetadata queries

DatasourceMetadata - 图1info

Apache Druid supports two query languages: Druid SQL and native queries. This document describes a query type that is only available in the native language.

Data Source Metadata queries return metadata information for a dataSource. These queries return information about:

  • The timestamp of the latest ingested event for the dataSource. This is the ingested event without any consideration of rollup.

The grammar for these queries is:

  1. {
  2.     "queryType" : "dataSourceMetadata",
  3.     "dataSource": "sample_datasource"
  4. }

There are 2 main parts to a Data Source Metadata query:

propertydescriptionrequired?
queryTypeThis String should always be “dataSourceMetadata”; this is the first thing Apache Druid looks at to figure out how to interpret the queryyes
dataSourceA String or Object defining the data source to query, very similar to a table in a relational database. See DataSource for more information.yes
contextSee Contextno

The format of the result is:

  1. [ {
  2.   "timestamp" : "2013-05-09T18:24:00.000Z",
  3.   "result" : {
  4.     "maxIngestedEventTime" : "2013-05-09T18:24:09.007Z"
  5.   }
  6. } ]