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* Refresh query docs. Larger changes: - New doc: querying/datasource.md describes the various kinds of datasources you can use, and has examples for both SQL and native. - New doc: querying/query-execution.md describes how native queries are executed at a high level. It doesn't go into the details of specific query engines or how queries run at a per-segment level. But I think it would be good to add or link that content here in the future. - Refreshed doc: querying/sql.md updated to refer to joins, reformatted a bit, added a new "Query translation" section that explains how queries are translated from SQL to native, and removed configuration details (moved to configuration/index.md). - Refreshed doc: querying/joins.md updated to refer to join datasources. Smaller changes: - Add helpful banners to the top of query documentation pages telling people whether a given page describes SQL, native, or both. - Add SQL metrics to operations/metrics.md. - Add some color and cross-links in various places. - Add native query component docs to the sidebar, and renamed them so they look nicer. - Remove Select query from the sidebar. - Fix Broker SQL configs in configuration/index.md. Remove them from querying/sql.md. - Combined querying/searchquery.md and querying/searchqueryspec.md. * Updates. * Fix numbering. * Fix glitches. * Add new words to spellcheck file. * Assorted changes. * Further adjustments. * Add missing punctuation.
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| id | title | sidebar_label |
|---|---|---|
| datasourcemetadataquery | DatasourceMetadata queries | DatasourceMetadata |
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 latest ingested event for the dataSource. This is the ingested event without any consideration of rollup.
The grammar for these queries is:
{
"queryType" : "dataSourceMetadata",
"dataSource": "sample_datasource"
}
There are 2 main parts to a Data Source Metadata query:
| property | description | required? |
|---|---|---|
| queryType | This String should always be "dataSourceMetadata"; this is the first thing Apache Druid looks at to figure out how to interpret the query | yes |
| dataSource | A String or Object defining the data source to query, very similar to a table in a relational database. See DataSource for more information. | yes |
| context | See Context | no |
The format of the result is:
[ {
"timestamp" : "2013-05-09T18:24:00.000Z",
"result" : {
"maxIngestedEventTime" : "2013-05-09T18:24:09.007Z"
}
} ]