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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.
61 lines
2.1 KiB
Markdown
61 lines
2.1 KiB
Markdown
---
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id: datasourcemetadataquery
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title: "DatasourceMetadata queries"
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sidebar_label: "DatasourceMetadata"
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---
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<!--
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~ Licensed to the Apache Software Foundation (ASF) under one
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~ or more contributor license agreements. See the NOTICE file
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~ distributed with this work for additional information
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~ regarding copyright ownership. The ASF licenses this file
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~ to you under the Apache License, Version 2.0 (the
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~ "License"); you may not use this file except in compliance
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~ with the License. You may obtain a copy of the License at
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~
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~ http://www.apache.org/licenses/LICENSE-2.0
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~
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~ Unless required by applicable law or agreed to in writing,
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~ software distributed under the License is distributed on an
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~ "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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~ KIND, either express or implied. See the License for the
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~ specific language governing permissions and limitations
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~ under the License.
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> Apache Druid supports two query languages: [Druid SQL](sql.md) and [native queries](querying.md).
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> This document describes a query
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> type that is only available in the native language.
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Data Source Metadata queries return metadata information for a dataSource. These queries return information about:
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* The timestamp of latest ingested event for the dataSource. This is the ingested event without any consideration of rollup.
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The grammar for these queries is:
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```json
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{
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"queryType" : "dataSourceMetadata",
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"dataSource": "sample_datasource"
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}
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```
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There are 2 main parts to a Data Source Metadata query:
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|property|description|required?|
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|--------|-----------|---------|
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|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|
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|dataSource|A String or Object defining the data source to query, very similar to a table in a relational database. See [DataSource](../querying/datasource.md) for more information.|yes|
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|context|See [Context](../querying/query-context.md)|no|
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The format of the result is:
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```json
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[ {
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"timestamp" : "2013-05-09T18:24:00.000Z",
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"result" : {
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"maxIngestedEventTime" : "2013-05-09T18:24:09.007Z"
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}
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} ]
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```
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