| <!DOCTYPE html> |
| <html lang="en"> |
| <head> |
| <meta charset="UTF-8" /> |
| <meta name="viewport" content="width=device-width, initial-scale=1.0"> |
| <meta name="description" content="Apache Druid"> |
| <meta name="keywords" content="druid,kafka,database,analytics,streaming,real-time,real time,apache,open source"> |
| <meta name="author" content="Apache Software Foundation"> |
| |
| <title>Druid | Apache Druid (incubating) vs SQL-on-Hadoop</title> |
| |
| <link rel="alternate" type="application/atom+xml" href="/feed"> |
| <link rel="shortcut icon" href="/img/favicon.png"> |
| |
| <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.2/css/all.css" integrity="sha384-fnmOCqbTlWIlj8LyTjo7mOUStjsKC4pOpQbqyi7RrhN7udi9RwhKkMHpvLbHG9Sr" crossorigin="anonymous"> |
| |
| <link href='//fonts.googleapis.com/css?family=Open+Sans+Condensed:300,700,300italic|Open+Sans:300italic,400italic,600italic,400,300,600,700' rel='stylesheet' type='text/css'> |
| |
| <link rel="stylesheet" href="/css/bootstrap-pure.css?v=1.1"> |
| <link rel="stylesheet" href="/css/base.css?v=1.1"> |
| <link rel="stylesheet" href="/css/header.css?v=1.1"> |
| <link rel="stylesheet" href="/css/footer.css?v=1.1"> |
| <link rel="stylesheet" href="/css/syntax.css?v=1.1"> |
| <link rel="stylesheet" href="/css/docs.css?v=1.1"> |
| |
| <script> |
| (function() { |
| var cx = '000162378814775985090:molvbm0vggm'; |
| var gcse = document.createElement('script'); |
| gcse.type = 'text/javascript'; |
| gcse.async = true; |
| gcse.src = (document.location.protocol == 'https:' ? 'https:' : 'http:') + |
| '//cse.google.com/cse.js?cx=' + cx; |
| var s = document.getElementsByTagName('script')[0]; |
| s.parentNode.insertBefore(gcse, s); |
| })(); |
| </script> |
| |
| |
| </head> |
| |
| <body> |
| <!-- Start page_header include --> |
| <script src="//ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js"></script> |
| |
| <div class="top-navigator"> |
| <div class="container"> |
| <div class="left-cont"> |
| <a class="logo" href="/"><span class="druid-logo"></span></a> |
| </div> |
| <div class="right-cont"> |
| <ul class="links"> |
| <li class=""><a href="/technology">Technology</a></li> |
| <li class=""><a href="/use-cases">Use Cases</a></li> |
| <li class=""><a href="/druid-powered">Powered By</a></li> |
| <li class=""><a href="/docs/latest/design/">Docs</a></li> |
| <li class=""><a href="/community/">Community</a></li> |
| <li class="header-dropdown"> |
| <a>Apache</a> |
| <div class="header-dropdown-menu"> |
| <a href="https://www.apache.org/" target="_blank">Foundation</a> |
| <a href="https://www.apache.org/events/current-event" target="_blank">Events</a> |
| <a href="https://www.apache.org/licenses/" target="_blank">License</a> |
| <a href="https://www.apache.org/foundation/thanks.html" target="_blank">Thanks</a> |
| <a href="https://www.apache.org/security/" target="_blank">Security</a> |
| <a href="https://www.apache.org/foundation/sponsorship.html" target="_blank">Sponsorship</a> |
| </div> |
| </li> |
| <li class=" button-link"><a href="/downloads.html">Download</a></li> |
| </ul> |
| </div> |
| </div> |
| <div class="action-button menu-icon"> |
| <span class="fa fa-bars"></span> MENU |
| </div> |
| <div class="action-button menu-icon-close"> |
| <span class="fa fa-times"></span> MENU |
| </div> |
| </div> |
| |
| <script type="text/javascript"> |
| var $menu = $('.right-cont'); |
| var $menuIcon = $('.menu-icon'); |
| var $menuIconClose = $('.menu-icon-close'); |
| |
| function showMenu() { |
| $menu.fadeIn(100); |
| $menuIcon.fadeOut(100); |
| $menuIconClose.fadeIn(100); |
| } |
| |
| $menuIcon.click(showMenu); |
| |
| function hideMenu() { |
| $menu.fadeOut(100); |
| $menuIconClose.fadeOut(100); |
| $menuIcon.fadeIn(100); |
| } |
| |
| $menuIconClose.click(hideMenu); |
| |
| $(window).resize(function() { |
| if ($(window).width() >= 840) { |
| $menu.fadeIn(100); |
| $menuIcon.fadeOut(100); |
| $menuIconClose.fadeOut(100); |
| } |
| else { |
| $menu.fadeOut(100); |
| $menuIcon.fadeIn(100); |
| $menuIconClose.fadeOut(100); |
| } |
| }); |
| </script> |
| |
| <!-- Stop page_header include --> |
| |
| |
| <div class="container doc-container"> |
| |
| |
| |
| |
| <p> Looking for the <a href="/docs/0.23.0/">latest stable documentation</a>?</p> |
| |
| |
| <div class="row"> |
| <div class="col-md-9 doc-content"> |
| <p> |
| <a class="btn btn-default btn-xs visible-xs-inline-block visible-sm-inline-block" href="#toc">Table of Contents</a> |
| </p> |
| <!-- |
| ~ 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. |
| --> |
| |
| <h1 id="apache-druid-incubating-vs-sql-on-hadoop-impala-drill-spark-sql-presto">Apache Druid (incubating) vs SQL-on-Hadoop (Impala/Drill/Spark SQL/Presto)</h1> |
| |
| <p>SQL-on-Hadoop engines provide an |
| execution engine for various data formats and data stores, and |
| many can be made to push down computations down to Druid, while providing a SQL interface to Druid.</p> |
| |
| <p>For a direct comparison between the technologies and when to only use one or the other, things basically comes down to your |
| product requirements and what the systems were designed to do.</p> |
| |
| <p>Druid was designed to</p> |
| |
| <ol> |
| <li>be an always on service</li> |
| <li>ingest data in real-time</li> |
| <li>handle slice-n-dice style ad-hoc queries</li> |
| </ol> |
| |
| <p>SQL-on-Hadoop engines generally sidestep Map/Reduce, instead querying data directly from HDFS or, in some cases, other storage systems. |
| Some of these engines (including Impala and Presto) can be colocated with HDFS data nodes and coordinate with them to achieve data locality for queries. |
| What does this mean? We can talk about it in terms of three general areas</p> |
| |
| <ol> |
| <li>Queries</li> |
| <li>Data Ingestion</li> |
| <li>Query Flexibility</li> |
| </ol> |
| |
| <h3 id="queries">Queries</h3> |
| |
| <p>Druid segments stores data in a custom column format. Segments are scanned directly as part of queries and each Druid server |
| calculates a set of results that are eventually merged at the Broker level. This means the data that is transferred between servers |
| are queries and results, and all computation is done internally as part of the Druid servers.</p> |
| |
| <p>Most SQL-on-Hadoop engines are responsible for query planning and execution for underlying storage layers and storage formats. |
| They are processes that stay on even if there is no query running (eliminating the JVM startup costs from Hadoop MapReduce). |
| Some (Impala/Presto) SQL-on-Hadoop engines have daemon processes that can be run where the data is stored, virtually eliminating network transfer costs. There is still |
| some latency overhead (e.g. serde time) associated with pulling data from the underlying storage layer into the computation layer. We are unaware of exactly |
| how much of a performance impact this makes.</p> |
| |
| <h3 id="data-ingestion">Data Ingestion</h3> |
| |
| <p>Druid is built to allow for real-time ingestion of data. You can ingest data and query it immediately upon ingestion, |
| the latency between how quickly the event is reflected in the data is dominated by how long it takes to deliver the event to Druid.</p> |
| |
| <p>SQL-on-Hadoop, being based on data in HDFS or some other backing store, are limited in their data ingestion rates by the |
| rate at which that backing store can make data available. Generally, the backing store is the biggest bottleneck for |
| how quickly data can become available.</p> |
| |
| <h3 id="query-flexibility">Query Flexibility</h3> |
| |
| <p>Druid's query language is fairly low level and maps to how Druid operates internally. Although Druid can be combined with a high level query |
| planner such as <a href="https://github.com/implydata/plywood">Plywood</a> to support most SQL queries and analytic SQL queries (minus joins among large tables), |
| base Druid is less flexible than SQL-on-Hadoop solutions for generic processing.</p> |
| |
| <p>SQL-on-Hadoop support SQL style queries with full joins.</p> |
| |
| <h2 id="druid-vs-parquet">Druid vs Parquet</h2> |
| |
| <p>Parquet is a column storage format that is designed to work with SQL-on-Hadoop engines. Parquet doesn't have a query execution engine, and instead |
| relies on external sources to pull data out of it.</p> |
| |
| <p>Druid's storage format is highly optimized for linear scans. Although Druid has support for nested data, Parquet's storage format is much |
| more hierachical, and is more designed for binary chunking. In theory, this should lead to faster scans in Druid.</p> |
| |
| </div> |
| <div class="col-md-3"> |
| <div class="searchbox"> |
| <gcse:searchbox-only></gcse:searchbox-only> |
| </div> |
| <div id="toc" class="nav toc hidden-print"> |
| </div> |
| </div> |
| </div> |
| </div> |
| |
| <!-- Start page_footer include --> |
| <footer class="druid-footer"> |
| <div class="container"> |
| <div class="text-center"> |
| <p> |
| <a href="/technology">Technology</a> ·  |
| <a href="/use-cases">Use Cases</a> ·  |
| <a href="/druid-powered">Powered by Druid</a> ·  |
| <a href="/docs/latest/">Docs</a> ·  |
| <a href="/community/">Community</a> ·  |
| <a href="/downloads.html">Download</a> ·  |
| <a href="/faq">FAQ</a> |
| </p> |
| </div> |
| <div class="text-center"> |
| <a title="Join the user group" href="https://groups.google.com/forum/#!forum/druid-user" target="_blank"><span class="fa fa-comments"></span></a> ·  |
| <a title="Follow Druid" href="https://twitter.com/druidio" target="_blank"><span class="fab fa-twitter"></span></a> ·  |
| <a title="GitHub" href="https://github.com/apache/druid" target="_blank"><span class="fab fa-github"></span></a> |
| </div> |
| <div class="text-center license"> |
| Copyright © 2020 <a href="https://www.apache.org/" target="_blank">Apache Software Foundation</a>.<br> |
| Except where otherwise noted, licensed under <a rel="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA 4.0</a>.<br> |
| Apache Druid, Druid, and the Druid logo are either registered trademarks or trademarks of The Apache Software Foundation in the United States and other countries. |
| </div> |
| </div> |
| </footer> |
| |
| <script async src="https://www.googletagmanager.com/gtag/js?id=UA-131010415-1"></script> |
| <script> |
| window.dataLayer = window.dataLayer || []; |
| function gtag(){dataLayer.push(arguments);} |
| gtag('js', new Date()); |
| gtag('config', 'UA-131010415-1'); |
| </script> |
| <script> |
| function trackDownload(type, url) { |
| ga('send', 'event', 'download', type, url); |
| } |
| </script> |
| <script src="//code.jquery.com/jquery.min.js"></script> |
| <script src="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script> |
| <script src="/assets/js/druid.js"></script> |
| <!-- stop page_footer include --> |
| |
| |
| <script> |
| $(function() { |
| $(".toc").load("/docs/0.14.1-incubating/toc.html"); |
| |
| // There is no way to tell when .gsc-input will be async loaded into the page so just try to set a placeholder until it works |
| var tries = 0; |
| var timer = setInterval(function() { |
| tries++; |
| if (tries > 300) clearInterval(timer); |
| var searchInput = $('input.gsc-input'); |
| if (searchInput.length) { |
| searchInput.attr('placeholder', 'Search'); |
| clearInterval(timer); |
| } |
| }, 100); |
| }); |
| </script> |
| </body> |
| </html> |
