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For history and tracking purposes, there are many instances of rev="CDH-1234" for various CDH- JIRA numbers. This produces no visible output, it's just FYI for the person editing the source. Removing all these now from the upstream doc source, so as not to have "CDH" all through the doc source files. Change-Id: I29089e5a31cd72e876b2ccb8375d1c10693c6aba Reviewed-on: http://gerrit.cloudera.org:8080/6349 Reviewed-by: Ambreen Kazi <ambreen.kazi@cloudera.com> Reviewed-by: John Russell <jrussell@cloudera.com> Tested-by: Impala Public Jenkins
418 lines
17 KiB
XML
418 lines
17 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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-->
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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
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<concept id="shell_commands">
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<title>impala-shell Command Reference</title>
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<titlealts audience="PDF"><navtitle>Command Reference</navtitle></titlealts>
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<prolog>
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<metadata>
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<data name="Category" value="Impala"/>
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<data name="Category" value="impala-shell"/>
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<data name="Category" value="SQL"/>
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<data name="Category" value="Data Analysts"/>
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<data name="Category" value="Developers"/>
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</metadata>
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</prolog>
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<conbody>
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<p>
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<indexterm audience="hidden">impala-shell</indexterm>
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Use the following commands within <codeph>impala-shell</codeph> to pass requests to the
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<codeph>impalad</codeph> daemon that the shell is connected to. You can enter a command interactively at the
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prompt, or pass it as the argument to the <codeph>-q</codeph> option of <codeph>impala-shell</codeph>. Most
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of these commands are passed to the Impala daemon as SQL statements; refer to the corresponding
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<xref href="impala_langref_sql.xml#langref_sql">SQL language reference sections</xref> for full syntax
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details.
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</p>
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<table>
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<tgroup cols="2">
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<colspec colname="1" colwidth="10*"/>
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<colspec colname="2" colwidth="40*"/>
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<thead>
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<row>
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<entry>
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Command
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</entry>
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<entry>
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Explanation
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</entry>
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</row>
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</thead>
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<tbody>
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<row id="alter_cmd">
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<entry>
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<p>
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<codeph>alter</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Changes the underlying structure or settings of an Impala table, or a table shared between Impala
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and Hive. See <xref href="impala_alter_table.xml#alter_table"/> and
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<xref href="impala_alter_view.xml#alter_view"/> for details.
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</p>
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</entry>
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</row>
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<row rev="1.2.2" id="compute_cmd">
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<entry>
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<p>
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<codeph>compute stats</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Gathers important performance-related information for a table, used by Impala to optimize queries.
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See <xref href="impala_compute_stats.xml#compute_stats"/> for details.
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</p>
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</entry>
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</row>
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<row id="connect_cmd">
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<entry>
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<p>
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<codeph>connect</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Connects to the specified instance of <codeph>impalad</codeph>. The default port of 21000 is
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assumed unless you provide another value. You can connect to any host in your cluster that is
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running <codeph>impalad</codeph>. If you connect to an instance of <codeph>impalad</codeph> that
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was started with an alternate port specified by the <codeph>--fe_port</codeph> flag, you must
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provide that alternate port. See <xref href="impala_connecting.xml#connecting"/> for examples.
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</p>
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<p conref="../shared/impala_common.xml#common/set_vs_connect"/>
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</entry>
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</row>
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<row id="describe_cmd">
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<entry>
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<p>
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<codeph>describe</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Shows the columns, column data types, and any column comments for a specified table.
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<codeph>DESCRIBE FORMATTED</codeph> shows additional information such as the HDFS data directory,
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partitions, and internal properties for the table. See <xref href="impala_describe.xml#describe"/>
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for details about the basic <codeph>DESCRIBE</codeph> output and the <codeph>DESCRIBE
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FORMATTED</codeph> variant. You can use <codeph>DESC</codeph> as shorthand for the
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<codeph>DESCRIBE</codeph> command.
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</p>
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</entry>
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</row>
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<row id="drop_cmd">
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<entry>
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<p>
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<codeph>drop</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Removes a schema object, and in some cases its associated data files. See
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<xref href="impala_drop_table.xml#drop_table"/>, <xref href="impala_drop_view.xml#drop_view"/>,
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<xref href="impala_drop_database.xml#drop_database"/>, and
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<xref href="impala_drop_function.xml#drop_function"/> for details.
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</p>
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</entry>
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</row>
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<row id="explain_cmd">
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<entry>
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<p>
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<codeph>explain</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Provides the execution plan for a query. <codeph>EXPLAIN</codeph> represents a query as a series of
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steps. For example, these steps might be map/reduce stages, metastore operations, or file system
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operations such as move or rename. See <xref href="impala_explain.xml#explain"/> and
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<xref href="impala_explain_plan.xml#perf_explain"/> for details.
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</p>
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</entry>
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</row>
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<row id="help_cmd">
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<entry>
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<p>
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<codeph>help</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Help provides a list of all available commands and options.
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</p>
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</entry>
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</row>
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<row id="history_cmd">
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<entry>
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<p>
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<codeph>history</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Maintains an enumerated cross-session command history. This history is stored in the
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<filepath>~/.impalahistory</filepath> file.
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</p>
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</entry>
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</row>
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<row id="insert_cmd">
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<entry>
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<p>
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<codeph>insert</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Writes the results of a query to a specified table. This either overwrites table data or appends
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data to the existing table content. See <xref href="impala_insert.xml#insert"/> for details.
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</p>
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</entry>
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</row>
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<row id="invalidate_metadata_cmd">
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<entry>
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<p>
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<codeph>invalidate metadata</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Updates <cmdname>impalad</cmdname> metadata for table existence and structure. Use this command
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after creating, dropping, or altering databases, tables, or partitions in Hive. See
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<xref href="impala_invalidate_metadata.xml#invalidate_metadata"/> for details.
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</p>
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</entry>
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</row>
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<row id="profile_cmd">
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<entry>
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<p>
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<codeph>profile</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Displays low-level information about the most recent query. Used for performance diagnosis and
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tuning. <ph rev="1.4.0"> The report starts with the same information as produced by the
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<codeph>EXPLAIN</codeph> statement and the <codeph>SUMMARY</codeph> command.</ph> See
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<xref href="impala_explain_plan.xml#perf_profile"/> for details.
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</p>
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</entry>
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</row>
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<row id="quit_cmd">
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<entry>
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<p>
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<codeph>quit</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Exits the shell. Remember to include the final semicolon so that the shell recognizes the end of
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the command.
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</p>
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</entry>
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</row>
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<row id="refresh_cmd">
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<entry>
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<p>
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<codeph>refresh</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Refreshes <cmdname>impalad</cmdname> metadata for the locations of HDFS blocks corresponding to
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Impala data files. Use this command after loading new data files into an Impala table through Hive
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or through HDFS commands. See <xref href="impala_refresh.xml#refresh"/> for details.
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</p>
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</entry>
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</row>
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<row id="select_cmd">
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<entry>
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<p>
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<codeph>select</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Specifies the data set on which to complete some action. All information returned from
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<codeph>select</codeph> can be sent to some output such as the console or a file or can be used to
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complete some other element of query. See <xref href="impala_select.xml#select"/> for details.
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</p>
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</entry>
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</row>
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<row id="set_cmd">
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<entry>
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<p>
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<codeph>set</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Manages query options for an <cmdname>impala-shell</cmdname> session. The available options are the
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ones listed in <xref href="impala_query_options.xml#query_options"/>. These options are used for
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query tuning and troubleshooting. Issue <codeph>SET</codeph> with no arguments to see the current
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query options, either based on the <cmdname>impalad</cmdname> defaults, as specified by you at
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<cmdname>impalad</cmdname> startup, or based on earlier <codeph>SET</codeph> statements in the same
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session. To modify option values, issue commands with the syntax <codeph>set
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<varname>option</varname>=<varname>value</varname></codeph>. To restore an option to its default,
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use the <codeph>unset</codeph> command. Some options take Boolean values of <codeph>true</codeph>
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and <codeph>false</codeph>. Others take numeric arguments, or quoted string values.
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</p>
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<p conref="../shared/impala_common.xml#common/set_vs_connect"/>
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<p rev="2.0.0">
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In Impala 2.0 and later, <codeph>SET</codeph> is available as a SQL statement for any kind of
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application, not only through <cmdname>impala-shell</cmdname>. See
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<xref href="impala_set.xml#set"/> for details.
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</p>
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<p rev="2.5.0 IMPALA-2180">
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In Impala 2.5 and later, you can use <codeph>SET</codeph> to define your own substitution variables
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within an <cmdname>impala-shell</cmdname> session.
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Within a SQL statement, you substitute the value by using the notation <codeph>${var:<varname>variable_name</varname>}</codeph>.
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</p>
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</entry>
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</row>
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<row id="shell_cmd">
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<entry>
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<p>
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<codeph>shell</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Executes the specified command in the operating system shell without exiting
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<codeph>impala-shell</codeph>. You can use the <codeph>!</codeph> character as shorthand for the
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<codeph>shell</codeph> command.
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</p>
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<note>
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Quote any instances of the <codeph>--</codeph> or <codeph>/*</codeph> tokens to avoid them being
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interpreted as the start of a comment. To embed comments within <codeph>source</codeph> or
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<codeph>!</codeph> commands, use the shell comment character <codeph>#</codeph> before the comment
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portion of the line.
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</note>
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</entry>
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</row>
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<row id="show_cmd">
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<entry>
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<p>
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<codeph>show</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Displays metastore data for schema objects created and accessed through Impala, Hive, or both.
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<codeph>show</codeph> can be used to gather information about objects such as databases, tables, and functions.
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See <xref href="impala_show.xml#show"/> for details.
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</p>
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</entry>
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</row>
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<row id="source_cmd" rev="IMPALA-3397">
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<entry>
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<p>
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<codeph>source</codeph> or <codeph>src</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Executes one or more statements residing in a specified file from the local filesystem.
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Allows you to perform the same kinds of batch operations as with the <codeph>-f</codeph> option,
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but interactively within the interpreter. The file can contain SQL statements and other
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<cmdname>impala-shell</cmdname> commands, including additional <codeph>SOURCE</codeph> commands
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to perform a flexible sequence of actions. Each command or statement, except the last one in the file,
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must end with a semicolon.
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See <xref href="impala_shell_running_commands.xml#shell_running_commands"/> for examples.
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</p>
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</entry>
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</row>
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<row rev="1.4.0" id="summary_cmd">
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<entry>
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<p>
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<codeph>summary</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Summarizes the work performed in various stages of a query. It provides a higher-level view of the
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information displayed by the <codeph>EXPLAIN</codeph> command. Added in Impala 1.4.0. See
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<xref href="impala_explain_plan.xml#perf_summary"/> for details about the report format
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and how to interpret it.
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</p>
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<p rev="2.3.0">
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In <keyword keyref="impala23_full"/> and higher, you can see a continuously updated report of
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the summary information while a query is in progress.
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See <xref href="impala_live_summary.xml#live_summary"/> for details.
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</p>
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</entry>
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</row>
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<row id="unset_cmd">
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<entry>
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<p>
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<codeph>unset</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Removes any user-specified value for a query option and returns the option to its default value.
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See <xref href="impala_query_options.xml#query_options"/> for the available query options.
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</p>
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<p rev="2.5.0 IMPALA-2180">
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In <keyword keyref="impala25_full"/> and higher, it can also remove user-specified substitution variables
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using the notation <codeph>UNSET VAR:<varname>variable_name</varname></codeph>.
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</p>
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</entry>
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</row>
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<row id="use_cmd">
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<entry>
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<p>
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<codeph>use</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Indicates the database against which to execute subsequent commands. Lets you avoid using fully
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qualified names when referring to tables in databases other than <codeph>default</codeph>. See
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<xref href="impala_use.xml#use"/> for details. Not effective with the <codeph>-q</codeph> option,
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because that option only allows a single statement in the argument.
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</p>
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</entry>
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</row>
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<row id="version_cmd">
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<entry>
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<p>
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<codeph>version</codeph>
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</p>
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</entry>
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<entry>
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<p>
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Returns Impala version information.
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</p>
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</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</conbody>
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</concept>
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