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   <p>Apache Impala</p>
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   <h1 class="title topictitle1" id="ariaid-title1">Modifying Impala Startup Options</h1>


   <div class="body conbody">

     <p class="p">
       The configuration options for the Impala daemons let you choose which hosts and ports to
       use for the services that run on a single host, specify directories for logging, control
       resource usage and security, and specify other aspects of the Impala software.
     </p>

     <p class="p toc inpage"></p>

   </div>

   <nav role="navigation" class="related-links"><div class="familylinks"><div class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_processes.html">Starting Impala</a></div></div></nav><article class="topic concept nested1" aria-labelledby="ariaid-title2" id="config_options__config_options_noncm">

     <h2 class="title topictitle2" id="ariaid-title2">Configuring Impala Startup Options through the Command Line</h2>

     <div class="body conbody">

       <p class="p">
         The Impala server, <code class="ph codeph">statestore</code>, and catalog services start up using
         values provided in a defaults file, <span class="ph filepath">/etc/default/impala</span>.
       </p>

       <p class="p">
         This file includes information about many resources used by Impala. Most of the defaults
         included in this file should be effective in most cases. For example, typically you
         would not change the definition of the <code class="ph codeph">CLASSPATH</code> variable, but you
         would always set the address used by the <code class="ph codeph">statestore</code> server. Some of the
         content you might modify includes:
       </p>


 <pre class="pre codeblock"><code>IMPALA_STATE_STORE_HOST=127.0.0.1
 IMPALA_STATE_STORE_PORT=24000
 IMPALA_BACKEND_PORT=22000
 IMPALA_LOG_DIR=/var/log/impala
 IMPALA_CATALOG_SERVICE_HOST=...
 IMPALA_STATE_STORE_HOST=...

 export IMPALA_STATE_STORE_ARGS=${IMPALA_STATE_STORE_ARGS:- \
     -log_dir=${IMPALA_LOG_DIR} -state_store_port=${IMPALA_STATE_STORE_PORT}}
 IMPALA_SERVER_ARGS=" \
 -log_dir=${IMPALA_LOG_DIR} \
 -catalog_service_host=${IMPALA_CATALOG_SERVICE_HOST} \
 -state_store_port=${IMPALA_STATE_STORE_PORT} \
 -state_store_host=${IMPALA_STATE_STORE_HOST} \
 -be_port=${IMPALA_BACKEND_PORT}"
 export ENABLE_CORE_DUMPS=${ENABLE_COREDUMPS:-false}</code></pre>

       <p class="p">
         To use alternate values, edit the defaults file, then restart all the Impala-related
         services so that the changes take effect. Restart the Impala server using the following
         commands:
       </p>

 <pre class="pre codeblock"><code>$ sudo service impala-server restart
 Stopping Impala Server:                                    [  OK  ]
 Starting Impala Server:                                    [  OK  ]</code></pre>

       <p class="p">
         Restart the Impala StateStore using the following commands:
       </p>

 <pre class="pre codeblock"><code>$ sudo service impala-state-store restart
 Stopping Impala State Store Server:                        [  OK  ]
 Starting Impala State Store Server:                        [  OK  ]</code></pre>

       <p class="p">
         Restart the Impala Catalog Service using the following commands:
       </p>

 <pre class="pre codeblock"><code>$ sudo service impala-catalog restart
 Stopping Impala Catalog Server:                            [  OK  ]
 Starting Impala Catalog Server:                            [  OK  ]</code></pre>

       <p class="p">
         Some common settings to change include:
       </p>

       <ul class="ul">
         <li class="li">
           <p class="p">
             StateStore address. Where practical, put the <code class="ph codeph">statestored</code> on a
             separate host not running the <span class="keyword cmdname">impalad</span> daemon. In that recommended
             configuration, the <span class="keyword cmdname">impalad</span> daemon cannot refer to the
             <code class="ph codeph">statestored</code> server using the loopback address. If the
             <code class="ph codeph">statestored</code> is hosted on a machine with an IP address of
             192.168.0.27, change:
           </p>
 <pre class="pre codeblock"><code>IMPALA_STATE_STORE_HOST=127.0.0.1</code></pre>
           <p class="p">
             to:
           </p>
 <pre class="pre codeblock"><code>IMPALA_STATE_STORE_HOST=192.168.0.27</code></pre>
         </li>

         <li class="li">
           <p class="p">
             Catalog server address (including both the hostname and the port number). Update the
             value of the <code class="ph codeph">IMPALA_CATALOG_SERVICE_HOST</code> variable. Where practical,
             run the catalog server on the same host as the <code class="ph codeph">statestore</code>. In that
             recommended configuration, the <span class="keyword cmdname">impalad</span> daemon cannot refer to the
             catalog server using the loopback address. If the catalog service is hosted on a
             machine with an IP address of 192.168.0.27, add the following line:
           </p>
 <pre class="pre codeblock"><code>IMPALA_CATALOG_SERVICE_HOST=192.168.0.27:26000</code></pre>
           <p class="p">
             The <span class="ph filepath">/etc/default/impala</span> defaults file currently does not define
             an <code class="ph codeph">IMPALA_CATALOG_ARGS</code> environment variable, but if you add one it
             will be recognized by the service startup/shutdown script. Add a definition for this
             variable to <span class="ph filepath">/etc/default/impala</span> and add the option
             <code class="ph codeph">‑‑catalog_service_host=<var class="keyword varname">hostname</var></code>. If
             the port is different than the default 26000, also add the option
             <code class="ph codeph">‑‑catalog_service_port=<var class="keyword varname">port</var></code>.
           </p>
         </li>

         <li class="li" id="config_options_noncm__mem_limit">
           <p class="p">
             Memory limits. You can limit the amount of memory available to Impala. For example,
             to allow Impala to use no more than 70% of system memory, change:
           </p>

 <pre class="pre codeblock"><code>export IMPALA_SERVER_ARGS=${IMPALA_SERVER_ARGS:- \
     -log_dir=${IMPALA_LOG_DIR} \
     -state_store_port=${IMPALA_STATE_STORE_PORT} \
     -state_store_host=${IMPALA_STATE_STORE_HOST} \
     -be_port=${IMPALA_BACKEND_PORT}}</code></pre>
           <p class="p">
             to:
           </p>
 <pre class="pre codeblock"><code>export IMPALA_SERVER_ARGS=${IMPALA_SERVER_ARGS:- \
     -log_dir=${IMPALA_LOG_DIR} -state_store_port=${IMPALA_STATE_STORE_PORT} \
     -state_store_host=${IMPALA_STATE_STORE_HOST} \
     -be_port=${IMPALA_BACKEND_PORT} -mem_limit=70%}</code></pre>
           <p class="p">
             You can specify the memory limit using absolute notation such as
             <code class="ph codeph">500m</code> or <code class="ph codeph">2G</code>, or as a percentage of physical memory
             such as <code class="ph codeph">60%</code>.
           </p>

           <div class="note note note_note"><span class="note__title notetitle">Note:</span>
             Queries that exceed the specified memory limit are aborted. Percentage limits are
             based on the physical memory of the machine and do not consider cgroups.
           </div>
         </li>

         <li class="li">
           <p class="p">
             Core dump enablement. To enable core dumps, change:
           </p>
 <pre class="pre codeblock"><code>export ENABLE_CORE_DUMPS=${ENABLE_COREDUMPS:-false}</code></pre>
           <p class="p">
             to:
           </p>
 <pre class="pre codeblock"><code>export ENABLE_CORE_DUMPS=${ENABLE_COREDUMPS:-true}</code></pre>
           <div class="note note note_note"><span class="note__title notetitle">Note:</span>
         <ul class="ul">
           <li class="li">
             <p class="p">
               The location of core dump files may vary according to your operating system
               configuration.
             </p>
           </li>

           <li class="li">
             <p class="p">
               Other security settings may prevent Impala from writing core dumps even when this
               option is enabled.
             </p>
           </li>
         </ul>
       </div>
         </li>

         <li class="li">
           <p class="p">
             Authorization. Specify the
               <code class="ph codeph">‑‑server_name</code> option as part of the
               <code class="ph codeph">IMPALA_SERVER_ARGS</code> and
               <code class="ph codeph">IMPALA_CATALOG_ARGS</code> settings to enable the core
             Impala support for authorization. See <a class="xref" href="impala_authorization.html#secure_startup">impala_authorization.html#secure_startup</a> for details.
           </p>
         </li>

         <li class="li">
           <p class="p">
             Auditing for successful or blocked Impala queries, another aspect of security.
             Specify the
             <code class="ph codeph">‑‑audit_event_log_dir=<var class="keyword varname">directory_path</var></code>
             option and optionally the
             <code class="ph codeph">‑‑max_audit_event_log_file_size=<var class="keyword varname">number_of_queries</var></code>
             and <code class="ph codeph">‑‑abort_on_failed_audit_event</code> options as part of
             the <code class="ph codeph">IMPALA_SERVER_ARGS</code> settings, for each Impala node, to enable
             and customize auditing. See
             <a class="xref" href="impala_auditing.html#auditing">Auditing Impala Operations</a> for details.
           </p>
         </li>

         <li class="li">
           <p class="p">
             Password protection for the Impala web UI, which listens on port 25000 by default.
             This feature involves adding some or all of the
             <code class="ph codeph">‑‑webserver_password_file</code>,
             <code class="ph codeph">‑‑webserver_authentication_domain</code>, and
             <code class="ph codeph">‑‑webserver_certificate_file</code> options to the
             <code class="ph codeph">IMPALA_SERVER_ARGS</code> and <code class="ph codeph">IMPALA_STATE_STORE_ARGS</code>
             settings. See
             <a class="xref" href="impala_security_guidelines.html#security_guidelines">Security Guidelines for Impala</a> for
             details.
           </p>
         </li>

         <li class="li" id="config_options_noncm__default_query_options">
           <div class="p">
             Another setting you might add to <code class="ph codeph">IMPALA_SERVER_ARGS</code> is a
             comma-separated list of query options and values:
 <pre class="pre codeblock"><code>‑‑default_query_options='<var class="keyword varname">option</var>=<var class="keyword varname">value</var>,<var class="keyword varname">option</var>=<var class="keyword varname">value</var>,...'
 </code></pre>
             These options control the behavior of queries performed by this
             <span class="keyword cmdname">impalad</span> instance. The option values you specify here override the
             default values for
             <a class="xref" href="impala_set.html">Impala query
             options</a>, as shown by the <code class="ph codeph">SET</code> statement in
             <span class="keyword cmdname">impala-shell</span>.
           </div>
         </li>

         <li class="li">
           <p class="p">
             During troubleshooting, <span class="keyword">the appropriate support channel</span> might direct you to change
             other values, particularly for <code class="ph codeph">IMPALA_SERVER_ARGS</code>, to work around
             issues or gather debugging information.
           </p>
         </li>
       </ul>

       <div class="note note note_note"><span class="note__title notetitle">Note:</span>
         <p class="p">
           These startup options for the <span class="keyword cmdname">impalad</span> daemon are different from the
           command-line options for the <span class="keyword cmdname">impala-shell</span> command. For the
           <span class="keyword cmdname">impala-shell</span> options, see
           <a class="xref" href="impala_shell_options.html#shell_options">impala-shell Configuration Options</a>.
         </p>
       </div>

       <p class="p toc inpage"></p>

     </div>

   </article>

   <article class="topic concept nested1" aria-labelledby="ariaid-title3" id="config_options__config_options_checking">

     <h2 class="title topictitle2" id="ariaid-title3">Checking the Values of Impala Configuration Options</h2>

     <div class="body conbody">

       <p class="p">
         You can check the current runtime value of all these settings through the Impala web
         interface, available by default at
         <code class="ph codeph">http://<var class="keyword varname">impala_hostname</var>:25000/varz</code> for the
         <span class="keyword cmdname">impalad</span> daemon,
         <code class="ph codeph">http://<var class="keyword varname">impala_hostname</var>:25010/varz</code> for the
         <span class="keyword cmdname">statestored</span> daemon, or
         <code class="ph codeph">http://<var class="keyword varname">impala_hostname</var>:25020/varz</code> for the
         <span class="keyword cmdname">catalogd</span> daemon.
       </p>

     </div>

   </article>

   <article class="topic concept nested1" aria-labelledby="ariaid-title4" id="config_options__config_options_catalogd">

     <h2 class="title topictitle2" id="ariaid-title4">Startup Options for catalogd Daemon</h2>

     <div class="body conbody">

       <p class="p">
         The <span class="keyword cmdname">catalogd</span> daemon implements the Impala Catalog service, which
         broadcasts metadata changes to all the Impala nodes when Impala creates a table, inserts
         data, or performs other kinds of DDL and DML operations.
       </p>

       <div class="p">
         Use <code class="ph codeph">‑‑load_catalog_in_background</code> option to control when the
         metadata of a table is loaded.
         <ul class="ul">
           <li class="li">
             If set to <code class="ph codeph">false</code>, the metadata of a table is loaded when it is
             referenced for the first time. This means that the first run of a particular query
             can be slower than subsequent runs. Starting in Impala 2.2, the default for
             <code class="ph codeph">‑‑load_catalog_in_background</code> is <code class="ph codeph">false</code>.
           </li>

           <li class="li">
             If set to <code class="ph codeph">true</code>, the catalog service attempts to load metadata for a
             table even if no query needed that metadata. So metadata will possibly be already
             loaded when the first query that would need it is run. However, for the following
             reasons, we recommend not to set the option to <code class="ph codeph">true</code>.
             <ul class="ul">
               <li class="li">
                 Background load can interfere with query-specific metadata loading. This can
                 happen on startup or after invalidating metadata, with a duration depending on
                 the amount of metadata, and can lead to a seemingly random long running queries
                 that are difficult to diagnose.
               </li>

               <li class="li">
                 Impala may load metadata for tables that are possibly never used, potentially
                 increasing catalog size and consequently memory usage for both catalog service
                 and Impala Daemon.
               </li>
             </ul>
           </li>
         </ul>
       </div>

     </div>

   </article>

 </article></main></body></html>
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	SYSTEM "about:legacy-compat">
	<html lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta charset="UTF-8"><meta name="copyright" content="(C) Copyright 2023"><meta name="DC.rights.owner" content="(C) Copyright 2023"><meta name="DC.Type" content="concept"><meta name="DC.Relation" scheme="URI" content="../topics/impala_processes.html"><meta name="prodname" content="Impala"><meta name="prodname" content="Impala"><meta name="version" content="Impala 3.4.x"><meta name="version" content="Impala 3.4.x"><meta name="DC.Format" content="XHTML"><meta name="DC.Identifier" content="config_options"><link rel="stylesheet" type="text/css" href="../css/commonltr.css"><link rel="stylesheet" type="text/css" href="../css/dita-ot-doc.css"><title>Modifying Impala Startup Options</title></head><body id="config_options"><header role="banner"><!--
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	<p>Apache Impala</p>
	<hr>
	</div></header><nav role="toc"><ul><li><a href="../topics/impala_intro.html">Introducing Apache Impala</a></li><li><a href="../topics/impala_concepts.html">Concepts and Architecture</a></li><li><a href="../topics/impala_planning.html">Deployment Planning</a></li><li><a href="../topics/impala_install.html">Installing Impala</a></li><li><a href="../topics/impala_config.html">Managing Impala</a></li><li><a href="../topics/impala_upgrading.html">Upgrading Impala</a></li><li><a href="../topics/impala_processes.html">Starting Impala</a><ul><li class="active"><a href="../topics/impala_config_options.html">Modifying Impala Startup Options</a></li></ul></li><li><a href="../topics/impala_tutorial.html">Tutorials</a></li><li><a href="../topics/impala_admin.html">Administration</a></li><li><a href="../topics/impala_security.html">Impala Security</a></li><li><a href="../topics/impala_langref.html">SQL Reference</a></li><li><a href="../topics/impala_performance.html">Performance Tuning</a></li><li><a href="../topics/impala_scalability.html">Scalability Considerations</a></li><li><a href="../topics/impala_resource_management.html">Resource Management</a></li><li><a href="../topics/impala_partitioning.html">Partitioning</a></li><li><a href="../topics/impala_file_formats.html">File Formats</a></li><li><a href="../topics/impala_kudu.html">Using Impala to Query Kudu Tables</a></li><li><a href="../topics/impala_hbase.html">HBase Tables</a></li><li><a href="../topics/impala_iceberg.html">Iceberg Tables</a></li><li><a href="../topics/impala_s3.html">S3 Tables</a></li><li><a href="../topics/impala_adls.html">ADLS Tables</a></li><li><a href="../topics/impala_isilon.html">Isilon Storage</a></li><li><a href="../topics/impala_ozone.html">Ozone Storage</a></li><li><a href="../topics/impala_logging.html">Logging</a></li><li><a href="../topics/impala_client.html">Client Access</a></li><li><a href="../topics/impala_fault_tolerance.html">Fault Tolerance</a></li><li><a href="../topics/impala_troubleshooting.html">Troubleshooting Impala</a></li><li><a href="../topics/impala_ports.html">Ports Used by Impala</a></li><li><a href="../topics/impala_reserved_words.html">Impala Reserved Words</a></li><li><a href="../topics/impala_faq.html">Impala Frequently Asked Questions</a></li><li><a href="../topics/impala_release_notes.html">Impala Release Notes</a></li></ul></nav><main role="main"><article role="article" aria-labelledby="ariaid-title1">

	<h1 class="title topictitle1" id="ariaid-title1">Modifying Impala Startup Options</h1>



	<div class="body conbody">

	<p class="p">
	The configuration options for the Impala daemons let you choose which hosts and ports to
	use for the services that run on a single host, specify directories for logging, control
	resource usage and security, and specify other aspects of the Impala software.
	</p>

	<p class="p toc inpage"></p>

	</div>

	<nav role="navigation" class="related-links"><div class="familylinks"><div class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_processes.html">Starting Impala</a></div></div></nav><article class="topic concept nested1" aria-labelledby="ariaid-title2" id="config_options__config_options_noncm">

	<h2 class="title topictitle2" id="ariaid-title2">Configuring Impala Startup Options through the Command Line</h2>

	<div class="body conbody">

	<p class="p">
	The Impala server, <code class="ph codeph">statestore</code>, and catalog services start up using
	values provided in a defaults file, <span class="ph filepath">/etc/default/impala</span>.
	</p>

	<p class="p">
	This file includes information about many resources used by Impala. Most of the defaults
	included in this file should be effective in most cases. For example, typically you
	would not change the definition of the <code class="ph codeph">CLASSPATH</code> variable, but you
	would always set the address used by the <code class="ph codeph">statestore</code> server. Some of the
	content you might modify includes:
	</p>



	<pre class="pre codeblock"><code>IMPALA_STATE_STORE_HOST=127.0.0.1
	IMPALA_STATE_STORE_PORT=24000
	IMPALA_BACKEND_PORT=22000
	IMPALA_LOG_DIR=/var/log/impala
	IMPALA_CATALOG_SERVICE_HOST=...
	IMPALA_STATE_STORE_HOST=...

	export IMPALA_STATE_STORE_ARGS=${IMPALA_STATE_STORE_ARGS:- \
	-log_dir=${IMPALA_LOG_DIR} -state_store_port=${IMPALA_STATE_STORE_PORT}}
	IMPALA_SERVER_ARGS=" \
	-log_dir=${IMPALA_LOG_DIR} \
	-catalog_service_host=${IMPALA_CATALOG_SERVICE_HOST} \
	-state_store_port=${IMPALA_STATE_STORE_PORT} \
	-state_store_host=${IMPALA_STATE_STORE_HOST} \
	-be_port=${IMPALA_BACKEND_PORT}"
	export ENABLE_CORE_DUMPS=${ENABLE_COREDUMPS:-false}</code></pre>

	<p class="p">
	To use alternate values, edit the defaults file, then restart all the Impala-related
	services so that the changes take effect. Restart the Impala server using the following
	commands:
	</p>

	<pre class="pre codeblock"><code>$ sudo service impala-server restart
	Stopping Impala Server: [ OK ]
	Starting Impala Server: [ OK ]</code></pre>

	<p class="p">
	Restart the Impala StateStore using the following commands:
	</p>

	<pre class="pre codeblock"><code>$ sudo service impala-state-store restart
	Stopping Impala State Store Server: [ OK ]
	Starting Impala State Store Server: [ OK ]</code></pre>

	<p class="p">
	Restart the Impala Catalog Service using the following commands:
	</p>

	<pre class="pre codeblock"><code>$ sudo service impala-catalog restart
	Stopping Impala Catalog Server: [ OK ]
	Starting Impala Catalog Server: [ OK ]</code></pre>

	<p class="p">
	Some common settings to change include:
	</p>

	<ul class="ul">
	<li class="li">
	<p class="p">
	StateStore address. Where practical, put the <code class="ph codeph">statestored</code> on a
	separate host not running the <span class="keyword cmdname">impalad</span> daemon. In that recommended
	configuration, the <span class="keyword cmdname">impalad</span> daemon cannot refer to the
	<code class="ph codeph">statestored</code> server using the loopback address. If the
	<code class="ph codeph">statestored</code> is hosted on a machine with an IP address of
	192.168.0.27, change:
	</p>
	<pre class="pre codeblock"><code>IMPALA_STATE_STORE_HOST=127.0.0.1</code></pre>
	<p class="p">
	to:
	</p>
	<pre class="pre codeblock"><code>IMPALA_STATE_STORE_HOST=192.168.0.27</code></pre>
	</li>

	<li class="li">
	<p class="p">
	Catalog server address (including both the hostname and the port number). Update the
	value of the <code class="ph codeph">IMPALA_CATALOG_SERVICE_HOST</code> variable. Where practical,
	run the catalog server on the same host as the <code class="ph codeph">statestore</code>. In that
	recommended configuration, the <span class="keyword cmdname">impalad</span> daemon cannot refer to the
	catalog server using the loopback address. If the catalog service is hosted on a
	machine with an IP address of 192.168.0.27, add the following line:
	</p>
	<pre class="pre codeblock"><code>IMPALA_CATALOG_SERVICE_HOST=192.168.0.27:26000</code></pre>
	<p class="p">
	The <span class="ph filepath">/etc/default/impala</span> defaults file currently does not define
	an <code class="ph codeph">IMPALA_CATALOG_ARGS</code> environment variable, but if you add one it
	will be recognized by the service startup/shutdown script. Add a definition for this
	variable to <span class="ph filepath">/etc/default/impala</span> and add the option
	<code class="ph codeph">‑‑catalog_service_host=<var class="keyword varname">hostname</var></code>. If
	the port is different than the default 26000, also add the option
	<code class="ph codeph">‑‑catalog_service_port=<var class="keyword varname">port</var></code>.
	</p>
	</li>

	<li class="li" id="config_options_noncm__mem_limit">
	<p class="p">
	Memory limits. You can limit the amount of memory available to Impala. For example,
	to allow Impala to use no more than 70% of system memory, change:
	</p>

	<pre class="pre codeblock"><code>export IMPALA_SERVER_ARGS=${IMPALA_SERVER_ARGS:- \
	-log_dir=${IMPALA_LOG_DIR} \
	-state_store_port=${IMPALA_STATE_STORE_PORT} \
	-state_store_host=${IMPALA_STATE_STORE_HOST} \
	-be_port=${IMPALA_BACKEND_PORT}}</code></pre>
	<p class="p">
	to:
	</p>
	<pre class="pre codeblock"><code>export IMPALA_SERVER_ARGS=${IMPALA_SERVER_ARGS:- \
	-log_dir=${IMPALA_LOG_DIR} -state_store_port=${IMPALA_STATE_STORE_PORT} \
	-state_store_host=${IMPALA_STATE_STORE_HOST} \
	-be_port=${IMPALA_BACKEND_PORT} -mem_limit=70%}</code></pre>
	<p class="p">
	You can specify the memory limit using absolute notation such as
	<code class="ph codeph">500m</code> or <code class="ph codeph">2G</code>, or as a percentage of physical memory
	such as <code class="ph codeph">60%</code>.
	</p>

	<div class="note note note_note"><span class="note__title notetitle">Note:</span>
	Queries that exceed the specified memory limit are aborted. Percentage limits are
	based on the physical memory of the machine and do not consider cgroups.
	</div>
	</li>

	<li class="li">
	<p class="p">
	Core dump enablement. To enable core dumps, change:
	</p>
	<pre class="pre codeblock"><code>export ENABLE_CORE_DUMPS=${ENABLE_COREDUMPS:-false}</code></pre>
	<p class="p">
	to:
	</p>
	<pre class="pre codeblock"><code>export ENABLE_CORE_DUMPS=${ENABLE_COREDUMPS:-true}</code></pre>
	<div class="note note note_note"><span class="note__title notetitle">Note:</span>
	<ul class="ul">
	<li class="li">
	<p class="p">
	The location of core dump files may vary according to your operating system
	configuration.
	</p>
	</li>

	<li class="li">
	<p class="p">
	Other security settings may prevent Impala from writing core dumps even when this
	option is enabled.
	</p>
	</li>
	</ul>
	</div>
	</li>

	<li class="li">
	<p class="p">
	Authorization. Specify the
	<code class="ph codeph">‑‑server_name</code> option as part of the
	<code class="ph codeph">IMPALA_SERVER_ARGS</code> and
	<code class="ph codeph">IMPALA_CATALOG_ARGS</code> settings to enable the core
	Impala support for authorization. See <a class="xref" href="impala_authorization.html#secure_startup">impala_authorization.html#secure_startup</a> for details.
	</p>
	</li>

	<li class="li">
	<p class="p">
	Auditing for successful or blocked Impala queries, another aspect of security.
	Specify the
	<code class="ph codeph">‑‑audit_event_log_dir=<var class="keyword varname">directory_path</var></code>
	option and optionally the
	<code class="ph codeph">‑‑max_audit_event_log_file_size=<var class="keyword varname">number_of_queries</var></code>
	and <code class="ph codeph">‑‑abort_on_failed_audit_event</code> options as part of
	the <code class="ph codeph">IMPALA_SERVER_ARGS</code> settings, for each Impala node, to enable
	and customize auditing. See
	<a class="xref" href="impala_auditing.html#auditing">Auditing Impala Operations</a> for details.
	</p>
	</li>

	<li class="li">
	<p class="p">
	Password protection for the Impala web UI, which listens on port 25000 by default.
	This feature involves adding some or all of the
	<code class="ph codeph">‑‑webserver_password_file</code>,
	<code class="ph codeph">‑‑webserver_authentication_domain</code>, and
	<code class="ph codeph">‑‑webserver_certificate_file</code> options to the
	<code class="ph codeph">IMPALA_SERVER_ARGS</code> and <code class="ph codeph">IMPALA_STATE_STORE_ARGS</code>
	settings. See
	<a class="xref" href="impala_security_guidelines.html#security_guidelines">Security Guidelines for Impala</a> for
	details.
	</p>
	</li>

	<li class="li" id="config_options_noncm__default_query_options">
	<div class="p">
	Another setting you might add to <code class="ph codeph">IMPALA_SERVER_ARGS</code> is a
	comma-separated list of query options and values:
	<pre class="pre codeblock"><code>‑‑default_query_options='<var class="keyword varname">option</var>=<var class="keyword varname">value</var>,<var class="keyword varname">option</var>=<var class="keyword varname">value</var>,...'
	</code></pre>
	These options control the behavior of queries performed by this
	<span class="keyword cmdname">impalad</span> instance. The option values you specify here override the
	default values for
	<a class="xref" href="impala_set.html">Impala query
	options</a>, as shown by the <code class="ph codeph">SET</code> statement in
	<span class="keyword cmdname">impala-shell</span>.
	</div>
	</li>

	<li class="li">
	<p class="p">
	During troubleshooting, <span class="keyword">the appropriate support channel</span> might direct you to change
	other values, particularly for <code class="ph codeph">IMPALA_SERVER_ARGS</code>, to work around
	issues or gather debugging information.
	</p>
	</li>
	</ul>

	<div class="note note note_note"><span class="note__title notetitle">Note:</span>
	<p class="p">
	These startup options for the <span class="keyword cmdname">impalad</span> daemon are different from the
	command-line options for the <span class="keyword cmdname">impala-shell</span> command. For the
	<span class="keyword cmdname">impala-shell</span> options, see
	<a class="xref" href="impala_shell_options.html#shell_options">impala-shell Configuration Options</a>.
	</p>
	</div>

	<p class="p toc inpage"></p>

	</div>

	</article>

	<article class="topic concept nested1" aria-labelledby="ariaid-title3" id="config_options__config_options_checking">

	<h2 class="title topictitle2" id="ariaid-title3">Checking the Values of Impala Configuration Options</h2>

	<div class="body conbody">

	<p class="p">
	You can check the current runtime value of all these settings through the Impala web
	interface, available by default at
	<code class="ph codeph">http://<var class="keyword varname">impala_hostname</var>:25000/varz</code> for the
	<span class="keyword cmdname">impalad</span> daemon,
	<code class="ph codeph">http://<var class="keyword varname">impala_hostname</var>:25010/varz</code> for the
	<span class="keyword cmdname">statestored</span> daemon, or
	<code class="ph codeph">http://<var class="keyword varname">impala_hostname</var>:25020/varz</code> for the
	<span class="keyword cmdname">catalogd</span> daemon.
	</p>

	</div>

	</article>

	<article class="topic concept nested1" aria-labelledby="ariaid-title4" id="config_options__config_options_catalogd">

	<h2 class="title topictitle2" id="ariaid-title4">Startup Options for catalogd Daemon</h2>

	<div class="body conbody">

	<p class="p">
	The <span class="keyword cmdname">catalogd</span> daemon implements the Impala Catalog service, which
	broadcasts metadata changes to all the Impala nodes when Impala creates a table, inserts
	data, or performs other kinds of DDL and DML operations.
	</p>

	<div class="p">
	Use <code class="ph codeph">‑‑load_catalog_in_background</code> option to control when the
	metadata of a table is loaded.
	<ul class="ul">
	<li class="li">
	If set to <code class="ph codeph">false</code>, the metadata of a table is loaded when it is
	referenced for the first time. This means that the first run of a particular query
	can be slower than subsequent runs. Starting in Impala 2.2, the default for
	<code class="ph codeph">‑‑load_catalog_in_background</code> is <code class="ph codeph">false</code>.
	</li>

	<li class="li">
	If set to <code class="ph codeph">true</code>, the catalog service attempts to load metadata for a
	table even if no query needed that metadata. So metadata will possibly be already
	loaded when the first query that would need it is run. However, for the following
	reasons, we recommend not to set the option to <code class="ph codeph">true</code>.
	<ul class="ul">
	<li class="li">
	Background load can interfere with query-specific metadata loading. This can
	happen on startup or after invalidating metadata, with a duration depending on
	the amount of metadata, and can lead to a seemingly random long running queries
	that are difficult to diagnose.
	</li>

	<li class="li">
	Impala may load metadata for tables that are possibly never used, potentially
	increasing catalog size and consequently memory usage for both catalog service
	and Impala Daemon.
	</li>
	</ul>
	</li>
	</ul>
	</div>

	</div>

	</article>

	</article></main></body></html>