writer-jill commented on code in PR #18252: URL: https://github.com/apache/druid/pull/18252#discussion_r2251947802
########## docs/querying/dart.md: ########## @@ -0,0 +1,144 @@ +--- +id: dart +title: "SQL queries using the Dart query profile" +sidebar_label: "Dart query profile" +description: The Dart query profile for the MSQ engine is an alternative to the native query engine that offers better parallelism and better performance for certain types of queries. +--- + +import Tabs from '@theme/Tabs'; +import TabItem from '@theme/TabItem'; + +<!-- + ~ Licensed to the Apache Software Foundation (ASF) under one + ~ or more contributor license agreements. See the NOTICE file + ~ distributed with this work for additional information + ~ regarding copyright ownership. The ASF licenses this file + ~ to you under the Apache License, Version 2.0 (the + ~ License); you may not use this file except in compliance + ~ with the License. You may obtain a copy of the License at + ~ + ~ http://www.apache.org/licenses/LICENSE-2.0 + ~ + ~ Unless required by applicable law or agreed to in writing, + ~ software distributed under the License is distributed on an + ~ AS IS BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + ~ KIND, either express or implied. See the License for the + ~ specific language governing permissions and limitations + ~ under the License. + --> + +:::info[Experimental] + +Dart is experimental. Use it in situations where it fits your use case better than the native query engine. But be aware that Dart has not received as much testing as the other query engines. + +::: + + +Dart is a profile of the MSQ engine that runs SELECT queries on Brokers and Historicals instead of on tasks. The Brokers act as controllers and the Historicals act as workers. + +Use Dart as an alternative to the native query engine since it offers better parallelism, excelling at queries that involve: + +- large joins, which Dart performs using parallel sort-merges +- high-cardinality exact groupBys Review Comment: ```suggestion - High-cardinality exact groupBy operations. ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
