| <?xml version="1.0" encoding="UTF-8"?> |
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| <!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
| <concept id="shell_commands"> |
| |
| <title>impala-shell Command Reference</title> |
| <titlealts audience="PDF"><navtitle>Command Reference</navtitle></titlealts> |
| <prolog> |
| <metadata> |
| <data name="Category" value="Impala"/> |
| <data name="Category" value="impala-shell"/> |
| <data name="Category" value="SQL"/> |
| <data name="Category" value="Data Analysts"/> |
| <data name="Category" value="Developers"/> |
| </metadata> |
| </prolog> |
| |
| <conbody> |
| |
| <p> |
| <indexterm audience="hidden">impala-shell</indexterm> |
| Use the following commands within <codeph>impala-shell</codeph> to pass requests to the |
| <codeph>impalad</codeph> daemon that the shell is connected to. You can enter a command interactively at the |
| prompt, or pass it as the argument to the <codeph>-q</codeph> option of <codeph>impala-shell</codeph>. Most |
| of these commands are passed to the Impala daemon as SQL statements; refer to the corresponding |
| <xref href="impala_langref_sql.xml#langref_sql">SQL language reference sections</xref> for full syntax |
| details. |
| </p> |
| |
| <table> |
| <tgroup cols="2"> |
| <colspec colname="1" colwidth="10*"/> |
| <colspec colname="2" colwidth="40*"/> |
| <thead> |
| <row> |
| <entry> |
| Command |
| </entry> |
| <entry> |
| Explanation |
| </entry> |
| </row> |
| </thead> |
| <tbody> |
| <row id="alter_cmd"> |
| <entry> |
| <p> |
| <codeph>alter</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Changes the underlying structure or settings of an Impala table, or a table shared between Impala |
| and Hive. See <xref href="impala_alter_table.xml#alter_table"/> and |
| <xref href="impala_alter_view.xml#alter_view"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row rev="1.2.2" id="compute_cmd"> |
| <entry> |
| <p> |
| <codeph>compute stats</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Gathers important performance-related information for a table, used by Impala to optimize queries. |
| See <xref href="impala_compute_stats.xml#compute_stats"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="connect_cmd"> |
| <entry> |
| <p> |
| <codeph>connect</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Connects to the specified instance of <codeph>impalad</codeph>. The default port of 21000 is |
| assumed unless you provide another value. You can connect to any host in your cluster that is |
| running <codeph>impalad</codeph>. If you connect to an instance of <codeph>impalad</codeph> that |
| was started with an alternate port specified by the <codeph>--fe_port</codeph> flag, you must |
| provide that alternate port. See <xref href="impala_connecting.xml#connecting"/> for examples. |
| </p> |
| |
| <p conref="../shared/impala_common.xml#common/set_vs_connect"/> |
| </entry> |
| </row> |
| <row id="describe_cmd"> |
| <entry> |
| <p> |
| <codeph>describe</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Shows the columns, column data types, and any column comments for a specified table. |
| <codeph>DESCRIBE FORMATTED</codeph> shows additional information such as the HDFS data directory, |
| partitions, and internal properties for the table. See <xref href="impala_describe.xml#describe"/> |
| for details about the basic <codeph>DESCRIBE</codeph> output and the <codeph>DESCRIBE |
| FORMATTED</codeph> variant. You can use <codeph>DESC</codeph> as shorthand for the |
| <codeph>DESCRIBE</codeph> command. |
| </p> |
| </entry> |
| </row> |
| <row id="drop_cmd"> |
| <entry> |
| <p> |
| <codeph>drop</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Removes a schema object, and in some cases its associated data files. See |
| <xref href="impala_drop_table.xml#drop_table"/>, <xref href="impala_drop_view.xml#drop_view"/>, |
| <xref href="impala_drop_database.xml#drop_database"/>, and |
| <xref href="impala_drop_function.xml#drop_function"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="explain_cmd"> |
| <entry> |
| <p> |
| <codeph>explain</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Provides the execution plan for a query. <codeph>EXPLAIN</codeph> represents a query as a series of |
| steps. For example, these steps might be map/reduce stages, metastore operations, or file system |
| operations such as move or rename. See <xref href="impala_explain.xml#explain"/> and |
| <xref href="impala_explain_plan.xml#perf_explain"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="help_cmd"> |
| <entry> |
| <p> |
| <codeph>help</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Help provides a list of all available commands and options. |
| </p> |
| </entry> |
| </row> |
| <row id="history_cmd"> |
| <entry> |
| <p> |
| <codeph>history</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Maintains an enumerated cross-session command history. This history is stored in the |
| <filepath>~/.impalahistory</filepath> file. |
| </p> |
| </entry> |
| </row> |
| <row id="insert_cmd"> |
| <entry> |
| <p> |
| <codeph>insert</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Writes the results of a query to a specified table. This either overwrites table data or appends |
| data to the existing table content. See <xref href="impala_insert.xml#insert"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="invalidate_metadata_cmd"> |
| <entry> |
| <p> |
| <codeph>invalidate metadata</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Updates <cmdname>impalad</cmdname> metadata for table existence and structure. Use this command |
| after creating, dropping, or altering databases, tables, or partitions in Hive. See |
| <xref href="impala_invalidate_metadata.xml#invalidate_metadata"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="profile_cmd"> |
| <entry> |
| <p> |
| <codeph>profile</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Displays low-level information about the most recent query. Used for performance diagnosis and |
| tuning. <ph rev="1.4.0"> The report starts with the same information as produced by the |
| <codeph>EXPLAIN</codeph> statement and the <codeph>SUMMARY</codeph> command.</ph> See |
| <xref href="impala_explain_plan.xml#perf_profile"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="quit_cmd"> |
| <entry> |
| <p> |
| <codeph>quit</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Exits the shell. Remember to include the final semicolon so that the shell recognizes the end of |
| the command. |
| </p> |
| </entry> |
| </row> |
| <row id="refresh_cmd"> |
| <entry> |
| <p> |
| <codeph>refresh</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Refreshes <cmdname>impalad</cmdname> metadata for the locations of HDFS blocks corresponding to |
| Impala data files. Use this command after loading new data files into an Impala table through Hive |
| or through HDFS commands. See <xref href="impala_refresh.xml#refresh"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="rerun_cmd" rev="2.10.0 IMPALA-992"> |
| <entry> |
| <p> |
| <codeph>rerun</codeph> or <codeph>@</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Executes a previous <cmdname>impala-shell</cmdname> command again, |
| from the list of commands displayed by the <codeph>history</codeph> |
| command. These could be SQL statements, or commands specific to |
| <cmdname>impala-shell</cmdname> such as <codeph>quit</codeph> |
| or <codeph>profile</codeph>. |
| </p> |
| <p> |
| Specify an integer argument. A positive integer |
| <codeph>N</codeph> represents the command labelled |
| <codeph>N</codeph> in the output of the |
| <codeph>HISTORY</codeph> command. A negative integer |
| <codeph>-N</codeph> represents the <codeph>N</codeph>th |
| command from the end of the list, such as -1 for the most recent |
| command. Commands that are executed again do not produce new |
| entries in the <codeph>HISTORY</codeph> output list. |
| </p> |
| </entry> |
| </row> |
| <row id="select_cmd"> |
| <entry> |
| <p> |
| <codeph>select</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Specifies the data set on which to complete some action. All information returned from |
| <codeph>select</codeph> can be sent to some output such as the console or a file or can be used to |
| complete some other element of query. See <xref href="impala_select.xml#select"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="set_cmd"> |
| <entry> |
| <p> |
| <codeph>set</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Manages query options for an <cmdname>impala-shell</cmdname> |
| session. The available options are the ones listed in <xref |
| href="impala_query_options.xml#query_options"/>. These options |
| are used for query tuning and troubleshooting. Issue |
| <codeph>SET</codeph> with no arguments to see the current |
| query options, either based on the <cmdname>impalad</cmdname> |
| defaults, as specified by you at <cmdname>impalad</cmdname> |
| startup, or based on earlier <codeph>SET</codeph> statements in |
| the same session. To modify option values, issue commands with |
| the syntax <codeph>set |
| <varname>option</varname>=<varname>value</varname></codeph>. |
| To restore an option to its default, use the |
| <codeph>unset</codeph> command. |
| </p> |
| |
| <p conref="../shared/impala_common.xml#common/set_vs_connect"/> |
| |
| <p rev="2.0.0"> |
| In Impala 2.0 and later, <codeph>SET</codeph> is |
| available as a SQL statement for any kind of application as well |
| as in <cmdname>impala-shell</cmdname>. See <xref |
| href="impala_set.xml#set"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="shell_cmd"> |
| <entry> |
| <p> |
| <codeph>shell</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Executes the specified command in the operating system shell without exiting |
| <codeph>impala-shell</codeph>. You can use the <codeph>!</codeph> character as shorthand for the |
| <codeph>shell</codeph> command. |
| </p> |
| |
| <note> |
| Quote any instances of the <codeph>--</codeph> or <codeph>/*</codeph> tokens to avoid them being |
| interpreted as the start of a comment. To embed comments within <codeph>source</codeph> or |
| <codeph>!</codeph> commands, use the shell comment character <codeph>#</codeph> before the comment |
| portion of the line. |
| </note> |
| </entry> |
| </row> |
| <row id="show_cmd"> |
| <entry> |
| <p> |
| <codeph>show</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Displays metastore data for schema objects created and accessed through Impala, Hive, or both. |
| <codeph>show</codeph> can be used to gather information about objects such as databases, tables, and functions. |
| See <xref href="impala_show.xml#show"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="source_cmd" rev="IMPALA-3397"> |
| <entry> |
| <p> |
| <codeph>source</codeph> or <codeph>src</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Executes one or more statements residing in a specified file from the local filesystem. |
| Allows you to perform the same kinds of batch operations as with the <codeph>-f</codeph> option, |
| but interactively within the interpreter. The file can contain SQL statements and other |
| <cmdname>impala-shell</cmdname> commands, including additional <codeph>SOURCE</codeph> commands |
| to perform a flexible sequence of actions. Each command or statement, except the last one in the file, |
| must end with a semicolon. |
| See <xref href="impala_shell_running_commands.xml#shell_running_commands"/> for examples. |
| </p> |
| </entry> |
| </row> |
| <row rev="1.4.0" id="summary_cmd"> |
| <entry> |
| <p> |
| <codeph>summary</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Summarizes the work performed in various stages of a query. It provides a higher-level view of the |
| information displayed by the <codeph>EXPLAIN</codeph> command. Added in Impala 1.4.0. See |
| <xref href="impala_explain_plan.xml#perf_summary"/> for details about the report format |
| and how to interpret it. |
| </p> |
| <p rev="2.3.0"> |
| In <keyword keyref="impala23_full"/> and higher, you can see a continuously updated report of |
| the summary information while a query is in progress. |
| See <xref href="impala_live_summary.xml#live_summary"/> for details. |
| </p> |
| </entry> |
| </row> |
| <row id="unset_cmd"> |
| <entry> |
| <p> |
| <codeph>unset</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Removes any user-specified value for a query option and returns the option to its default value. |
| See <xref href="impala_query_options.xml#query_options"/> for the available query options. |
| </p> |
| <p rev="2.5.0 IMPALA-2180"> |
| In <keyword keyref="impala25_full"/> and higher, it can also remove user-specified substitution variables |
| using the notation <codeph>UNSET VAR:<varname>variable_name</varname></codeph>. |
| </p> |
| </entry> |
| </row> |
| <row id="use_cmd"> |
| <entry> |
| <p> |
| <codeph>use</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Indicates the database against which to execute subsequent commands. Lets you avoid using fully |
| qualified names when referring to tables in databases other than <codeph>default</codeph>. See |
| <xref href="impala_use.xml#use"/> for details. Not effective with the <codeph>-q</codeph> option, |
| because that option only allows a single statement in the argument. |
| </p> |
| </entry> |
| </row> |
| <row id="version_cmd"> |
| <entry> |
| <p> |
| <codeph>version</codeph> |
| </p> |
| </entry> |
| <entry> |
| <p> |
| Returns Impala version information. |
| </p> |
| </entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| </conbody> |
| </concept> |