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Change-Id: Ifb95785a143939a94d55d3565364afe1e26c1f3d Reviewed-on: http://gerrit.cloudera.org:8080/10861 Reviewed-by: Adam Holley <aholley@cloudera.com> Reviewed-by: Fredy Wijaya <fwijaya@cloudera.com> Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
443 lines
18 KiB
XML
443 lines
18 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="rerun_cmd" rev="2.10.0 IMPALA-992">
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<entry>
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<p>
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<codeph>rerun</codeph> or <codeph>@</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 a previous <cmdname>impala-shell</cmdname> command again,
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from the list of commands displayed by the <codeph>history</codeph>
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command. These could be SQL statements, or commands specific to
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<cmdname>impala-shell</cmdname> such as <codeph>quit</codeph>
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or <codeph>profile</codeph>.
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</p>
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<p>
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Specify an integer argument. A positive integer
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<codeph>N</codeph> represents the command labelled
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<codeph>N</codeph> in the output of the
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<codeph>HISTORY</codeph> command. A negative integer
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<codeph>-N</codeph> represents the <codeph>N</codeph>th
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command from the end of the list, such as -1 for the most recent
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command. Commands that are executed again do not produce new
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entries in the <codeph>HISTORY</codeph> output list.
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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>
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session. The available options are the ones listed in <xref
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href="impala_query_options.xml#query_options"/>. These options
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are used for query tuning and troubleshooting. Issue
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<codeph>SET</codeph> with no arguments to see the current
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query options, either based on the <cmdname>impalad</cmdname>
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defaults, as specified by you at <cmdname>impalad</cmdname>
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startup, or based on earlier <codeph>SET</codeph> statements in
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the same session. To modify option values, issue commands with
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the syntax <codeph>set
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<varname>option</varname>=<varname>value</varname></codeph>.
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To restore an option to its default, use the
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<codeph>unset</codeph> command.
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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
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available as a SQL statement for any kind of application as well
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as in <cmdname>impala-shell</cmdname>. See <xref
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href="impala_set.xml#set"/> for details.
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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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