<!DOCTYPE html><html lang="en"><head><meta charSet="utf-8"/><meta http-equiv="X-UA-Compatible" content="IE=edge"/><title>Topology Tuning Guide · Apache Heron</title><meta name="viewport" content="width=device-width"/><meta name="generator" content="Docusaurus"/><meta name="description" content="&lt;!--"/><meta name="docsearch:version" content="0.20.4-incubating"/><meta name="docsearch:language" content="en"/><meta property="og:title" content="Topology Tuning Guide · Apache Heron"/><meta property="og:type" content="website"/><meta property="og:url" content="https://heron.apache.org/"/><meta property="og:description" content="&lt;!--"/><meta property="og:image" content="https://heron.apache.org/img/undraw_online.svg"/><meta name="twitter:card" content="summary"/><meta name="twitter:image" content="https://heron.apache.org/img/undraw_tweetstorm.svg"/><link rel="shortcut icon" href="/img/favicon-32x32.png"/><link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/default.min.css"/><link rel="alternate" type="application/atom+xml" href="https://heron.apache.org/blog/atom.xml" title="Apache Heron Blog ATOM Feed"/><link rel="alternate" type="application/rss+xml" href="https://heron.apache.org/blog/feed.xml" title="Apache Heron Blog RSS Feed"/><script>
              (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
              (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
              m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
              })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');

              ga('create', 'UA-198017384-1', 'auto');
              ga('send', 'pageview');
            </script><script type="text/javascript" src="https://buttons.github.io/buttons.js"></script><script type="text/javascript" src="/js/custom.js"></script><script type="text/javascript" src="/js/fix-location.js"></script><link rel="stylesheet" href="/css/main.css"/><script src="/js/codetabs.js"></script></head><body class="sideNavVisible separateOnPageNav"><div class="fixedHeaderContainer"><div class="headerWrapper wrapper"><header><a href="/"><img class="logo" src="/img/HeronTextLogo-small.png" alt="Apache Heron"/><h2 class="headerTitleWithLogo">Apache Heron</h2></a><a href="/versions"><h3>0.20.4-incubating</h3></a><div class="navigationWrapper navigationSlider"><nav class="slidingNav"><ul class="nav-site nav-site-internal"><li class=""><a href="/api/java" target="_self">Javadocs</a></li><li class=""><a href="/api/python" target="_self">Pydocs</a></li><li class="siteNavGroupActive"><a href="/docs/0.20.4-incubating/getting-started-local-single-node" target="_self">Docs</a></li><li class=""><a href="/download" target="_self">Downloads</a></li><li class=""><a href="#community" target="_self">Community</a></li><li class=""><a href="/blog/" target="_self">Blog</a></li><li class=""><a href="#apache" target="_self">Apache</a></li></ul></nav></div></header></div></div><div class="navPusher"><div class="docMainWrapper wrapper"><div class="container docsNavContainer" id="docsNav"><nav class="toc"><div class="toggleNav"><section class="navWrapper wrapper"><div class="navBreadcrumb wrapper"><div class="navToggle" id="navToggler"><div class="hamburger-menu"><div class="line1"></div><div class="line2"></div><div class="line3"></div></div></div><h2><i>›</i><span>Guides</span></h2><div class="tocToggler" id="tocToggler"><i class="icon-toc"></i></div></div><div class="navGroups"><div class="navGroup"><h3 class="navGroupCategoryTitle">Getting Started</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/getting-started-local-single-node">Local (Single Node)</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/getting-started-migrate-storm-topologies">Migrate Storm Topologies</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/getting-started-docker">Heron &amp; Docker</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/getting-started-troubleshooting-guide">Troubleshooting Guide</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Deployment</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/deployment-overview">Deployment Overiew</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/deployment-configuration">Configuration</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/deployment-api-server">The Heron API Server</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Topology Development APIs</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/topology-development-streamlet-api">The Heron Streamlet API for Java</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/topology-development-eco-api">The ECO API for Java</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/topology-development-topology-api-java">The Heron Topology API for Java</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/topology-development-topology-api-python">The Heron Topology API for Python</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/topology-development-streamlet-scala">The Heron Streamlet API for Scala</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Client API Docs</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/client-api-docs-overview">Client API Docs</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Guides</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/guides-effectively-once-java-topologies">Effectively Once Java Topologies</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/guides-data-model">Heron Data Model</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/guides-tuple-serialization">Tuple Serialization</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/guides-ui-guide">Heron UI Guide</a></li><li class="navListItem navListItemActive"><a class="navItem" href="/docs/0.20.4-incubating/guides-topology-tuning">Topology Tuning Guide</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/guides-packing-algorithms">Packing Algorithms</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/guides-simulator-mode">Simulator Mode</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/guides-troubeshooting-guide">Topology Troubleshooting Guide</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Heron Concepts</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/heron-design-goals">Heron Design Goals</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/heron-topology-concepts">Heron Topologies</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/heron-streamlet-concepts">Heron Streamlets</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/heron-architecture">Heron Architecture</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/heron-delivery-semantics">Heron Delivery Semantics</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">State Managers</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/state-managers-zookeeper">Zookeeper</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/state-managers-local-fs">Local File System</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Uploaders</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/uploaders-local-fs">Local File System</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/uploaders-hdfs">HDFS</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/uploaders-http">HTTP</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/uploaders-amazon-s3">Amazon S3</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/uploaders-scp">Secure Copy (SCP)</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Schedulers</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-k8s-by-hand">Kubernetes by hand</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-k8s-with-helm">Kubernetes with Helm</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-aurora-cluster">Aurora Cluster</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-aurora-local">Aurora Locally</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-local">Local Cluster</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-nomad">Nomad</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-mesos-local-mac">Mesos Cluster Locally</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-slurm">Slurm Cluster</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/schedulers-yarn">YARN Cluster</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Cluster Configuration</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/cluster-config-overview">Cluster Config Overview</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/cluster-config-system-level">System Level Configuration</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/cluster-config-instance">Heron Instance</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/cluster-config-metrics">Metrics Manager</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/cluster-config-stream">Stream Manager</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/cluster-config-tmanager">Topology Manager</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Observability</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/observability-prometheus">Prometheus</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/observability-graphite">Graphite</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/observability-scribe">Scribe</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">User Manuals</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/user-manuals-heron-cli">Heron Client</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/user-manuals-heron-explorer">Heron Explorer</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/user-manuals-tracker-rest">Heron Tracker REST API</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/user-manuals-heron-tracker-runbook">Heron Tracker Runbook</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/user-manuals-heron-ui-runbook">Heron UI Runbook</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/user-manuals-heron-shell">Heron Shell</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Compiling</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/compiling-overview">Compiling Overview</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/compiling-linux">Compiling on Linux</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/compiling-osx">Compiling on OS X</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/compiling-docker">Compiling With Docker</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/compiling-running-tests">Running Tests</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/compiling-code-organization">Code Organization</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Extending Heron</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/extending-heron-scheduler">Custom Scheduler</a></li><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/extending-heron-metric-sink">Custom Metrics Sink</a></li></ul></div><div class="navGroup"><h3 class="navGroupCategoryTitle">Heron Resources</h3><ul class=""><li class="navListItem"><a class="navItem" href="/docs/0.20.4-incubating/heron-resources-resources">Heron Resources</a></li></ul></div></div></section></div><script>
            var coll = document.getElementsByClassName('collapsible');
            var checkActiveCategory = true;
            for (var i = 0; i < coll.length; i++) {
              var links = coll[i].nextElementSibling.getElementsByTagName('*');
              if (checkActiveCategory){
                for (var j = 0; j < links.length; j++) {
                  if (links[j].classList.contains('navListItemActive')){
                    coll[i].nextElementSibling.classList.toggle('hide');
                    coll[i].childNodes[1].classList.toggle('rotate');
                    checkActiveCategory = false;
                    break;
                  }
                }
              }

              coll[i].addEventListener('click', function() {
                var arrow = this.childNodes[1];
                arrow.classList.toggle('rotate');
                var content = this.nextElementSibling;
                content.classList.toggle('hide');
              });
            }

            document.addEventListener('DOMContentLoaded', function() {
              createToggler('#navToggler', '#docsNav', 'docsSliderActive');
              createToggler('#tocToggler', 'body', 'tocActive');

              var headings = document.querySelector('.toc-headings');
              headings && headings.addEventListener('click', function(event) {
                var el = event.target;
                while(el !== headings){
                  if (el.tagName === 'A') {
                    document.body.classList.remove('tocActive');
                    break;
                  } else{
                    el = el.parentNode;
                  }
                }
              }, false);

              function createToggler(togglerSelector, targetSelector, className) {
                var toggler = document.querySelector(togglerSelector);
                var target = document.querySelector(targetSelector);

                if (!toggler) {
                  return;
                }

                toggler.onclick = function(event) {
                  event.preventDefault();

                  target.classList.toggle(className);
                };
              }
            });
        </script></nav></div><div class="container mainContainer"><div class="wrapper"><div class="post"><header class="postHeader"><h1 class="postHeaderTitle">Topology Tuning Guide</h1></header><article><div><span><!--
    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.
-->
<h3><a class="anchor" aria-hidden="true" id="overview"></a><a href="#overview" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Overview</h3>
<p>This guide provides basic steps at tuning a topology to utilize resources efficiently. Currently, resources are primarily measured in terms of CPU cores and RAM. In Heron, some of the basic parameters that are available to tune a topology are, but not limited to, the following:</p>
<ol>
<li>Container RAM</li>
<li>Container CPU</li>
<li>Component RAMs</li>
<li>Component Parallelisms</li>
<li>Number of Containers</li>
</ol>
<p>Note that tuning a topology may be difficult and may take multiple iterations. Before
proceeding, please make sure you understand concepts to understand the
terminology, as well as the reasoning behind taking these steps.</p>
<h3><a class="anchor" aria-hidden="true" id="steps-to-tune-a-topology"></a><a href="#steps-to-tune-a-topology" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Steps to Tune a Topology</h3>
<ol>
<li><p>Launch the topology with an initial estimate of resources. These can be based
on input data size, component logic, or experience from another working
topology.</p></li>
<li><p>Resolve any backpressure issues by increasing the parallelism or container
RAM, or CPU, or appropriately if backpressure is due to an external service.</p></li>
<li><p>Make sure there is no spout lag. In steady state, the topology should be able
to read the whole of data.</p></li>
<li><p>Repeat steps 2 and 3 until there is no backpressure and no spout lag.</p></li>
<li><p>By now, the CPU usage and RAM usage are stable. Based on daily of weekly data
trends, leave appropriate room for usage spikes, and cut down the rest of the
unused resources allocated to topology.</p></li>
</ol>
<p>While these steps seem simple, it might take some time to get the topology to
its optimal usage. Below are some of the tips that can be helpful during tuning
or in general.</p>
<h3><a class="anchor" aria-hidden="true" id="additional-tips"></a><a href="#additional-tips" aria-hidden="true" class="hash-link"><svg class="hash-link-icon" aria-hidden="true" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Additional Tips</h3>
<ol>
<li><p>If component RAMs for all the components is provided, that will the RAM
assigned to those instances. Use this configuration according to their
functionality to save of resources. By default, every instance is assigned
1GB of RAM, which can be higher that what it requires. Note that if container
RAM is specified, after setting aside some RAM for internal components of
Heron, rest of it is equally divided among all the instances present in the
container.</p></li>
<li><p>A memory intensive operation in bolts can result in GC issues. Be aware of
objects that might enter old generation, and cause memory starvation.</p></li>
<li><p>You can use <code>Scheme</code>s in spouts to sample down the data. This can helpful
when dealing with issues if writing to external services, or just trying to
get an early estimate of usage without utilizing much resources. Note that
this would still require 100% resource usage in spouts.</p></li>
</ol>
</span></div></article></div><div class="docs-prevnext"><a class="docs-prev button" href="/docs/0.20.4-incubating/guides-ui-guide"><span class="arrow-prev">← </span><span>Heron UI Guide</span></a><a class="docs-next button" href="/docs/0.20.4-incubating/guides-packing-algorithms"><span>Packing Algorithms</span><span class="arrow-next"> →</span></a></div></div></div><nav class="onPageNav"></nav></div><footer class="nav-footer" id="footer"><div class="apache-disclaimer">Apache Heron is an effort undergoing incubation at <a target="_blank" href="https://apache.org/">The Apache Software Foundation (ASF)</a> sponsored by the Apache Incubator PMC. Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF.<br/><br/>Apache®, the names of Apache projects, and the feather logo are either <a rel="external" href="https://www.apache.org/foundation/marks/list/">registered trademarks or trademarks</a> of the Apache Software Foundation in the United States and/or other countries.<br/><br/><div class="copyright-box">Copyright © 2023 the Apache Software Foundation, Apache Heron, Heron, 
  Apache, the Apache feather Logo, and the Apache Heron project logo are either registered 
  trademarks or trademarks of the Apache Software Foundation.</div></div><div class="apache-links"><a class="item" rel="external" href="https://incubator.apache.org/">Apache Incubator</a><div><a class="item" rel="external" href="https://www.apache.org/">About the ASF</a></div><div><a class="item" rel="external" href="https://www.apache.org/events/current-event">Events</a></div><div><a class="item" rel="external" href="https://www.apache.org/foundation/thanks.html">Thanks</a></div><div><a class="item" rel="external" href="https://www.apache.org/foundation/sponsorship.html">Become a Sponsor</a></div><div><a class="item" rel="external" href="https://www.apache.org/security/">Security</a></div><div><a class="item" rel="external" href="https://www.apache.org/licenses/">License</a></div></div></footer></div><script>window.twttr=(function(d,s, id){var js,fjs=d.getElementsByTagName(s)[0],t=window.twttr||{};if(d.getElementById(id))return t;js=d.createElement(s);js.id=id;js.src='https://platform.twitter.com/widgets.js';fjs.parentNode.insertBefore(js, fjs);t._e = [];t.ready = function(f) {t._e.push(f);};return t;}(document, 'script', 'twitter-wjs'));</script></body></html>