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Change-Id: I07ec0a197de8a625788a3b0485d5ecf237e554ba Reviewed-on: http://gerrit.cloudera.org:8080/22576 Reviewed-by: Zoltan Borok-Nagy <boroknagyz@cloudera.com> Tested-by: Peter Rozsa <prozsa@cloudera.com>
1820 lines
94 KiB
HTML
1820 lines
94 KiB
HTML
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<meta name="DC.Title" content="SHOW Statement" />
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<meta name="version" content="Impala 3.4.x" />
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<title>SHOW Statement</title>
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</head>
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<body id="show">
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<h1 class="title topictitle1" id="ariaid-title1">SHOW Statement</h1>
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<div class="body conbody">
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<p class="p"> The <code class="ph codeph">SHOW</code> statement is a flexible way to get information
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about different types of Impala objects. </p>
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<p class="p">
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<strong class="ph b">Syntax:</strong>
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</p>
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<pre class="pre codeblock"><code>SHOW DATABASES [[LIKE] '<var class="keyword varname">pattern</var>']
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SHOW SCHEMAS [[LIKE] '<var class="keyword varname">pattern</var>'] - an alias for SHOW DATABASES
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SHOW TABLES [IN <var class="keyword varname">database_name</var>] [[LIKE] '<var class="keyword varname">pattern</var>']
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<span class="ph">SHOW [AGGREGATE | ANALYTIC] FUNCTIONS [IN <var class="keyword varname">database_name</var>] [[LIKE] '<var class="keyword varname">pattern</var>']</span>
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<span class="ph">SHOW CREATE TABLE [<var class="keyword varname">database_name</var>].<var class="keyword varname">table_name</var></span>
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<span class="ph">SHOW CREATE VIEW [<var class="keyword varname">database_name</var>].<var class="keyword varname">view_name</var></span>
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<span class="ph">SHOW TABLE STATS [<var class="keyword varname">database_name</var>.]<var class="keyword varname">table_name</var></span>
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<span class="ph">SHOW COLUMN STATS [<var class="keyword varname">database_name</var>.]<var class="keyword varname">table_name</var></span>
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<span class="ph">SHOW PARTITIONS [<var class="keyword varname">database_name</var>.]<var class="keyword varname">table_name</var></span>
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<span class="ph">SHOW <span class="ph">[RANGE]</span> PARTITIONS [<var class="keyword varname">database_name</var>.]<var class="keyword varname">table_name</var></span>
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SHOW FILES IN [<var class="keyword varname">database_name</var>.]<var class="keyword varname">table_name</var> <span class="ph">[PARTITION (<var class="keyword varname">key_col_expression</var> [, <var class="keyword varname">key_col_expression</var>]</span>]
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<span class="ph">SHOW ROLES
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SHOW CURRENT ROLES
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SHOW ROLE GRANT GROUP <var class="keyword varname">group_name</var></span>
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<span class="ph">SHOW GRANT USER <var class="keyword varname">user_name</var>
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SHOW GRANT USER <var class="keyword varname">user_name</var> ON SERVER
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SHOW GRANT USER <var class="keyword varname">user_name</var> ON DATABASE <var class="keyword varname">database_name</var>
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SHOW GRANT USER <var class="keyword varname">user_name</var> ON TABLE <var class="keyword varname">database_name.table_name</var>
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SHOW GRANT USER <var class="keyword varname">user_name</var> ON URI <var class="keyword varname">uri</var></span>
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SHOW GRANT USER <var class="keyword varname">user_name</var> ON COLUMN <var class="keyword varname">database_name.table_name.column_name</var></code></pre>
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<pre class="pre codeblock"><code>SHOW GRANT ROLE <var class="keyword varname">role_name</var>
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SHOW GRANT ROLE <var class="keyword varname">role_name</var> ON SERVER
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SHOW GRANT ROLE <var class="keyword varname">role_name</var> ON DATABASE <var class="keyword varname">database_name</var>
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SHOW GRANT ROLE <var class="keyword varname">role_name</var> ON TABLE <var class="keyword varname">database_name.table_name</var>
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SHOW GRANT ROLE <var class="keyword varname">role_name</var> ON URI <var class="keyword varname">uri</var>
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SHOW GRANT ROLE <var class="keyword varname">role_name</var> ON COLUMN <var class="keyword varname">database_name.table_name.column_name</var></code></pre>
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<pre class="pre codeblock"><code>SHOW GRANT GROUP <var class="keyword varname">group_name</var> ON SERVER
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SHOW GRANT GROUP <var class="keyword varname">group_name</var> ON DATABASE <var class="keyword varname">database_name</var>
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SHOW GRANT GROUP <var class="keyword varname">group_name</var> ON TABLE <var class="keyword varname">database_name.table_name</var>
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SHOW GRANT GROUP <var class="keyword varname">group_name</var> ON URI <var class="keyword varname">uri</var>
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SHOW GRANT GROUP <var class="keyword varname">group_name</var> ON COLUMN <var class="keyword varname">database_name.table_name.column_name</var></code></pre>
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<p class="p"> Issue a <code class="ph codeph">SHOW <var class="keyword varname">object_type</var></code> statement
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to see the appropriate objects in the current database, or <code class="ph codeph">SHOW
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<var class="keyword varname">object_type</var> IN
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<var class="keyword varname">database_name</var></code> to see objects in a specific
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database. </p>
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<p class="p"> The optional <var class="keyword varname">pattern</var> argument is a quoted string
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literal, using Unix-style <code class="ph codeph">*</code> wildcards and allowing
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<code class="ph codeph">|</code> for alternation. The preceding <code class="ph codeph">LIKE</code>
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keyword is also optional. All object names are stored in lowercase, so use
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all lowercase letters in the pattern string. For example: </p>
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<pre class="pre codeblock"><code>SHOW DATABASES 'a*';
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SHOW DATABASES LIKE 'a*';
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SHOW TABLES IN some_db LIKE '*fact*';
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USE some_db;
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SHOW TABLES '*dim*|*fact*';</code></pre>
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<p class="p">
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<strong class="ph b">Cancellation:</strong> Cannot be cancelled.
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</p>
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<p class="p toc inpage"></p>
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</div>
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<div class="related-links">
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_langref_sql.html">Impala SQL Statements</a></div>
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</div>
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</div><div class="topic concept nested1" aria-labelledby="ariaid-title2" id="show_files">
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<h2 class="title topictitle2" id="ariaid-title2">SHOW FILES Statement</h2>
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<div class="body conbody">
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<p class="p">
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The <code class="ph codeph">SHOW FILES</code> statement displays the files that constitute a specified table,
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or a partition within a partitioned table. This syntax is available in <span class="keyword">Impala 2.2</span> and higher
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only. The output includes the names of the files, the size of each file, and the applicable partition
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for a partitioned table. The size includes a suffix of <code class="ph codeph">B</code> for bytes,
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<code class="ph codeph">MB</code> for megabytes, and <code class="ph codeph">GB</code> for gigabytes.
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</p>
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<div class="p">
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In <span class="keyword">Impala 2.8</span> and higher, you can use general
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expressions with operators such as <code class="ph codeph"><</code>, <code class="ph codeph">IN</code>,
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<code class="ph codeph">LIKE</code>, and <code class="ph codeph">BETWEEN</code> in the <code class="ph codeph">PARTITION</code>
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clause, instead of only equality operators. For example:
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<pre class="pre codeblock"><code>
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show files in sample_table partition (j < 5);
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show files in sample_table partition (k = 3, l between 1 and 10);
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show files in sample_table partition (month like 'J%');
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</code></pre>
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</div>
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<div class="note note"><span class="notetitle">Note:</span>
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This statement applies to tables and partitions stored on HDFS, or in the Amazon Simple Storage System (S3).
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It does not apply to views.
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It does not apply to tables mapped onto HBase <span class="ph">or Kudu</span>,
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because those data management systems do not use the same file-based storage layout.
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</div>
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<p class="p">
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<strong class="ph b">Usage notes:</strong>
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</p>
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<p class="p">
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You can use this statement to verify the results of your ETL process: that is, that
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the expected files are present, with the expected sizes. You can examine the file information
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to detect conditions such as empty files, missing files, or inefficient layouts due to
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a large number of small files. When you use <code class="ph codeph">INSERT</code> statements to copy
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from one table to another, you can see how the file layout changes due to file format
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conversions, compaction of small input files into large data blocks, and
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multiple output files from parallel queries and partitioned inserts.
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</p>
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<p class="p">
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The output from this statement does not include files that Impala considers to be hidden
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or invisible, such as those whose names start with a dot or an underscore, or that
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end with the suffixes <code class="ph codeph">.copying</code> or <code class="ph codeph">.tmp</code>.
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</p>
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<p class="p">
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The information for partitioned tables complements the output of the <code class="ph codeph">SHOW PARTITIONS</code>
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statement, which summarizes information about each partition. <code class="ph codeph">SHOW PARTITIONS</code>
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produces some output for each partition, while <code class="ph codeph">SHOW FILES</code> does not
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produce any output for empty partitions because they do not include any data files.
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</p>
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<p class="p">
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<strong class="ph b">HDFS permissions:</strong>
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</p>
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<p class="p">
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The user ID that the <span class="keyword cmdname">impalad</span> daemon runs under,
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typically the <code class="ph codeph">impala</code> user, must have read
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permission for all the table files, read and execute permission for all the directories that make up the table,
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and execute permission for the database directory and all its parent directories.
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</p>
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<p class="p">
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<strong class="ph b">Examples:</strong>
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</p>
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<p class="p">
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The following example shows a <code class="ph codeph">SHOW FILES</code> statement
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for an unpartitioned table using text format:
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</p>
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<pre class="pre codeblock"><code>[localhost:21000] > create table unpart_text (x bigint, s string);
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[localhost:21000] > insert into unpart_text (x, s) select id, name
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> from oreilly.sample_data limit 20e6;
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[localhost:21000] > show files in unpart_text;
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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| Path | Size | Partition | EC Policy |
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_text/35665776ef85cfaf_1012432410_data.0. | 448.31MB | | NONE |
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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[localhost:21000] > insert into unpart_text (x, s) select id, name from oreilly.sample_data limit 100e6;
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[localhost:21000] > show files in unpart_text;
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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| Path | Size | Partition | EC Policy
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_text/35665776ef85cfaf_1012432410_data.0. | 448.31MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_text/ac3dba252a8952b8_1663177415_data.0. | 2.19GB | | NONE |
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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</code></pre>
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<p class="p">
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This example illustrates how, after issuing some <code class="ph codeph">INSERT ... VALUES</code> statements,
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the table now contains some tiny files of just a few bytes. Such small files could cause inefficient processing of
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parallel queries that are expecting multi-megabyte input files. The example shows how you might compact the small files by doing
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an <code class="ph codeph">INSERT ... SELECT</code> into a different table, possibly converting the data to Parquet in the process:
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</p>
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<pre class="pre codeblock"><code>[localhost:21000] > insert into unpart_text values (10,'hello'), (20, 'world');
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[localhost:21000] > insert into unpart_text values (-1,'foo'), (-1000, 'bar');
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[localhost:21000] > show files in unpart_text;
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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| Path | Size | Partition | EC Policy |
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_text/4f11b8bdf8b6aa92_238145083_data.0. | 18B | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_text/35665776ef85cfaf_1012432410_data.0. | 448.31MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_text/ac3dba252a8952b8_1663177415_data.0. | 2.19GB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_text/cfb8252452445682_1868457216_data.0. | 17B | | NONE |
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+--------------------------------------------------------------------------------------+----------+-----------+-----------+
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[localhost:21000] > create table unpart_parq stored as parquet as select * from unpart_text;
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+---------------------------+
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| summary |
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+---------------------------+
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| Inserted 120000002 row(s) |
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+---------------------------+
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[localhost:21000] > show files in unpart_parq;
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+------------------------------------------------------------------------------------------+----------+-----------+-----------+
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| Path | Size | Partition | EC Policy |
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+------------------------------------------------------------------------------------------+----------+-----------+-----------+
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_parq/60798d96ba630184_549959007_data.0.parq | 255.36MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_parq/60798d96ba630184_549959007_data.1.parq | 178.52MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_parq/60798d96ba630185_549959007_data.0.parq | 255.37MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_parq/60798d96ba630185_549959007_data.1.parq | 57.71MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_parq/60798d96ba630186_2141167244_data.0.parq | 255.40MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_parq/60798d96ba630186_2141167244_data.1.parq | 175.52MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_parq/60798d96ba630187_1006832086_data.0.parq | 255.40MB | | NONE |
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| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/unpart_parq/60798d96ba630187_1006832086_data.1.parq | 214.61MB | | NONE |
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+------------------------------------------------------------------------------------------+----------+-----------+-----------+
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</code></pre>
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<p class="p">
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The following example shows a <code class="ph codeph">SHOW FILES</code> statement for a partitioned text table
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with data in two different partitions, and two empty partitions.
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The partitions with no data are not represented in the <code class="ph codeph">SHOW FILES</code> output.
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</p>
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<pre class="pre codeblock"><code>[localhost:21000] > create table part_text (x bigint, y int, s string)
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> partitioned by (year bigint, month bigint, day bigint);
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[localhost:21000] > insert overwrite part_text (x, y, s) partition (year=2014,month=1,day=1)
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> select id, val, name from oreilly.normalized_parquet
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where id between 1 and 1000000;
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[localhost:21000] > insert overwrite part_text (x, y, s) partition (year=2014,month=1,day=2)
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> select id, val, name from oreilly.normalized_parquet
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> where id between 1000001 and 2000000;
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[localhost:21000] > alter table part_text add partition (year=2014,month=1,day=3);
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[localhost:21000] > alter table part_text add partition (year=2014,month=1,day=4);
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[localhost:21000] > show partitions part_text;
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+-------+-------+-----+-------+--------+---------+--------------+-------------------+--------+-------------------+------------------------------------------------------------------------+-----------+
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| year | month | day | #Rows | #Files | Size | Bytes Cached | Cache Replication | Format | Incremental stats | Location | EC Policy |
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+-------+-------+-----+-------+--------+---------+--------------+-------------------+--------+-------------------+------------------------------------------------------------------------+-----------+
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| 2014 | 1 | 1 | -1 | 4 | 25.16MB | NOT CACHED | NOT CACHED | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=1 | NONE |
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| 2014 | 1 | 2 | -1 | 4 | 26.22MB | NOT CACHED | NOT CACHED | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=2 | NONE |
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| 2014 | 1 | 3 | -1 | 0 | 0B | NOT CACHED | NOT CACHED | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=3 | NONE |
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| 2014 | 1 | 4 | -1 | 0 | 0B | NOT CACHED | NOT CACHED | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=4 | NONE |
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| Total | | | -1 | 8 | 51.38MB | 0B | | | | | |
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+-------+-------+-----+-------+--------+---------+--------------+-------------------+--------+-------------------+------------------------------------------------------------------------+-----------+
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[localhost:21000] > show files in part_text;
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+------------------------------------------------------------------------------------------------------------+--------+-------------------------+-----------+
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| Path | Size | Partition | EC Policy |
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+------------------------------------------------------------------------------------------------------------+--------+-------------------------+-----------+
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=1/80732d9dc80689f_1418645991_data.0. | 5.77MB | year=2014/month=1/day=1 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=1/80732d9dc8068a0_1418645991_data.0. | 6.25MB | year=2014/month=1/day=1 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=1/80732d9dc8068a1_147082319_data.0. | 7.16MB | year=2014/month=1/day=1 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=1/80732d9dc8068a2_2111411753_data.0. | 5.98MB | year=2014/month=1/day=1 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=2/21a828cf494b5bbb_501271652_data.0. | 6.42MB | year=2014/month=1/day=2 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=2/21a828cf494b5bbc_501271652_data.0. | 6.62MB | year=2014/month=1/day=2 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=2/21a828cf494b5bbd_1393490200_data.0. | 6.98MB | year=2014/month=1/day=2 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_text/year=2014/month=1/day=2/21a828cf494b5bbe_1393490200_data.0. | 6.20MB | year=2014/month=1/day=2 | NONE |
|
|
+------------------------------------------------------------------------------------------------------------+--------+-------------------------+-----------+
|
|
</code></pre>
|
|
<p class="p">
|
|
The following example shows a <code class="ph codeph">SHOW FILES</code> statement for a partitioned Parquet table.
|
|
The number and sizes of files are different from the equivalent partitioned text table
|
|
used in the previous example, because <code class="ph codeph">INSERT</code> operations for Parquet tables
|
|
are parallelized differently than for text tables. (Also, the amount of data is so small
|
|
that it can be written to Parquet without involving all the hosts in this 4-node cluster.)
|
|
</p>
|
|
|
|
<pre class="pre codeblock"><code>[localhost:21000] > create table part_parq (x bigint, y int, s string) partitioned by (year bigint, month bigint, day bigint) stored as parquet;
|
|
[localhost:21000] > insert into part_parq partition (year,month,day) select x, y, s, year, month, day from partitioned_text;
|
|
[localhost:21000] > show partitions part_parq;
|
|
+-------+-------+-----+-------+--------+---------+--------------+-------------------+---------+-------------------+------------------------------------------------------------------------+-----------+
|
|
| year | month | day | #Rows | #Files | Size | Bytes Cached | Cache Replication | Format | Incremental stats | Location | EC Policy |
|
|
+-------+-------+-----+-------+--------+---------+--------------+-------------------+---------+-------------------+------------------------------------------------------------------------+-----------+
|
|
| 2014 | 1 | 1 | -1 | 3 | 17.89MB | NOT CACHED | NOT CACHED | PARQUET | false | hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_parq/year=2014/month=1/day=1 | NONE |
|
|
| 2014 | 1 | 2 | -1 | 3 | 17.89MB | NOT CACHED | NOT CACHED | PARQUET | false | hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_parq/year=2014/month=1/day=2 | NONE |
|
|
| Total | | | -1 | 6 | 35.79MB | 0B | | | | | |
|
|
+-------+-------+-----+-------+--------+---------+--------------+-------------------+---------+-------------------+------------------------------------------------------------------------+-----------+
|
|
[localhost:21000] > show files in part_parq;
|
|
+-----------------------------------------------------------------------------------------------+--------+-------------------------+-----------+
|
|
| Path | Size | Partition | EC Policy |
|
|
+-----------------------------------------------------------------------------------------------+--------+-------------------------+-----------+
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_parq/year=2014/month=1/day=1/1134113650_data.0.parq | 4.49MB | year=2014/month=1/day=1 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_parq/year=2014/month=1/day=1/617567880_data.0.parq | 5.14MB | year=2014/month=1/day=1 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_parq/year=2014/month=1/day=1/2099499416_data.0.parq | 8.27MB | year=2014/month=1/day=1 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_parq/year=2014/month=1/day=2/945567189_data.0.parq | 8.80MB | year=2014/month=1/day=2 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_parq/year=2014/month=1/day=2/2145850112_data.0.parq | 4.80MB | year=2014/month=1/day=2 | NONE |
|
|
| hdfs://<var class="keyword varname">impala_data_dir</var>/show_files.db/part_parq/year=2014/month=1/day=2/665613448_data.0.parq | 4.29MB | year=2014/month=1/day=2 | NONE |
|
|
+-----------------------------------------------------------------------------------------------+--------+-------------------------+-----------+
|
|
</code></pre>
|
|
<p class="p">
|
|
The following example shows output from the <code class="ph codeph">SHOW FILES</code> statement
|
|
for a table where the data files are stored in Amazon S3:
|
|
</p>
|
|
|
|
<pre class="pre codeblock"><code>[localhost:21000] > show files in s3_testing.sample_data_s3;
|
|
+-----------------------------------------------------------------------+---------+
|
|
| Path | Size |
|
|
+-----------------------------------------------------------------------+---------+
|
|
| s3a://impala-demo/sample_data/e065453cba1988a6_1733868553_data.0.parq | 24.84MB |
|
|
+-----------------------------------------------------------------------+---------+
|
|
</code></pre>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title3" id="show_roles">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title3">SHOW ROLES Statement</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
The <code class="ph codeph">SHOW ROLES</code> statement displays roles. This syntax
|
|
is available in <span class="keyword">Impala 2.0</span> and later only, when
|
|
you are using the Ranger authorization framework along with the Ranger
|
|
service, as described in <a class="xref" href="impala_authorization.html#sentry_service">Managing Privileges</a>.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
Depending on the roles set up within your organization by the <code class="ph codeph">CREATE ROLE</code> statement, the
|
|
output might look something like this:
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>show roles;
|
|
+-----------+
|
|
| role_name |
|
|
+-----------+
|
|
| analyst |
|
|
| role1 |
|
|
| sales |
|
|
| superuser |
|
|
| test_role |
|
|
+-----------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_authorization.html#authorization">Impala Authorization</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title4" id="show_current_role">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title4">SHOW CURRENT ROLES</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
The <code class="ph codeph">SHOW CURRENT ROLES</code> statement displays
|
|
roles assigned to the current user. This syntax is available in <span class="keyword">Impala 2.0</span> and later only, when you are using the Ranger
|
|
authorization framework along with the Ranger service, as described in
|
|
<a class="xref" href="impala_authorization.html#sentry_service">Managing Privileges</a>.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
Depending on the roles set up within your organization by the <code class="ph codeph">CREATE ROLE</code> statement, the
|
|
output might look something like this:
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>show current roles;
|
|
+-----------+
|
|
| role_name |
|
|
+-----------+
|
|
| role1 |
|
|
| superuser |
|
|
+-----------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_authorization.html#authorization">Impala Authorization</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title5" id="show_role_grant">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title5">SHOW ROLE GRANT GROUP Statement</h2>
|
|
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
The <code class="ph codeph">SHOW ROLE GRANT GROUP</code> statement lists
|
|
all the roles assigned to the specified group. This statement is only
|
|
allowed for Ranger administrative users and others users that are part
|
|
of the specified group. This syntax is available in <span class="keyword">Impala 2.0</span> and later only, when you are using the Ranger
|
|
authorization framework along with the Ranger service, as described in
|
|
<a class="xref" href="impala_authorization.html#sentry_service">Managing Privileges</a>.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_authorization.html#authorization">Impala Authorization</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title6" id="show_grant_role">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title6">SHOW GRANT ROLE Statement</h2>
|
|
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
|
|
The <code class="ph codeph">SHOW GRANT ROLE</code> statement list all the grants for
|
|
the given role name. This statement is only allowed for Ranger
|
|
administrative users and other users that have been granted the
|
|
specified role. This syntax is available in <span class="keyword">Impala 2.0</span> and later only, when you are using the Ranger
|
|
authorization framework along with the Ranger service, as described in
|
|
<a class="xref" href="impala_authorization.html#sentry_service">Managing Privileges</a>.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_authorization.html#authorization">Impala Authorization</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title7" id="show_grant_user">
|
|
<h2 class="title topictitle2" id="ariaid-title7">SHOW GRANT USER Statement</h2>
|
|
|
|
|
|
<div class="body conbody">
|
|
<p class="p">
|
|
The <code class="ph codeph">SHOW GRANT USER</code> statement shows the list of
|
|
privileges for a given user. This statement is only allowed for Ranger
|
|
administrative users. However, the current user can run <code class="ph codeph">SHOW
|
|
GRANT USER</code> for themselves.
|
|
</p>
|
|
|
|
<p class="p">
|
|
This syntax is available in <span class="keyword">Impala 3.1</span> and later
|
|
only, when you are using the Ranger authorization framework along with
|
|
the Ranger service, as described in <a class="xref" href="impala_authorization.html#sentry_service">Managing Privileges</a>.
|
|
</p>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_authorization.html#authorization">Impala Authorization</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title8" id="show_databases">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title8">SHOW DATABASES</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
The <code class="ph codeph">SHOW DATABASES</code> statement is often the first one you issue when connecting to an
|
|
instance for the first time. You typically issue <code class="ph codeph">SHOW DATABASES</code> to see the names you can
|
|
specify in a <code class="ph codeph">USE <var class="keyword varname">db_name</var></code> statement, then after switching to a database
|
|
you issue <code class="ph codeph">SHOW TABLES</code> to see the names you can specify in <code class="ph codeph">SELECT</code> and
|
|
<code class="ph codeph">INSERT</code> statements.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
In <span class="keyword">Impala 2.5</span> and higher, the output includes a second column showing any associated comment
|
|
for each database.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The output of <code class="ph codeph">SHOW DATABASES</code> includes the special <code class="ph codeph">_impala_builtins</code>
|
|
database, which lets you view definitions of built-in functions, as described under <code class="ph codeph">SHOW
|
|
FUNCTIONS</code>.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
This example shows how you might locate a particular table on an unfamiliar system. The
|
|
<code class="ph codeph">DEFAULT</code> database is the one you initially connect to; a database with that name is present
|
|
on every system. You can issue <code class="ph codeph">SHOW TABLES IN <var class="keyword varname">db_name</var></code> without going
|
|
into a database, or <code class="ph codeph">SHOW TABLES</code> once you are inside a particular database.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>[localhost:21000] > show databases;
|
|
+------------------+----------------------------------------------+
|
|
| name | comment |
|
|
+------------------+----------------------------------------------+
|
|
| _impala_builtins | System database for Impala builtin functions |
|
|
| default | Default Hive database |
|
|
| file_formats | |
|
|
+------------------+----------------------------------------------+
|
|
Returned 3 row(s) in 0.02s
|
|
[localhost:21000] > show tables in file_formats;
|
|
+--------------------+
|
|
| name |
|
|
+--------------------+
|
|
| parquet_table |
|
|
| rcfile_table |
|
|
| sequencefile_table |
|
|
| textfile_table |
|
|
+--------------------+
|
|
Returned 4 row(s) in 0.01s
|
|
[localhost:21000] > use file_formats;
|
|
[localhost:21000] > show tables like '*parq*';
|
|
+--------------------+
|
|
| name |
|
|
+--------------------+
|
|
| parquet_table |
|
|
+--------------------+
|
|
Returned 1 row(s) in 0.01s</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_databases.html#databases">Overview of Impala Databases</a>, <a class="xref" href="impala_create_database.html#create_database">CREATE DATABASE Statement</a>,
|
|
<a class="xref" href="impala_drop_database.html#drop_database">DROP DATABASE Statement</a>, <a class="xref" href="impala_use.html#use">USE Statement</a>
|
|
<a class="xref" href="impala_show.html#show_tables">SHOW TABLES Statement</a>,
|
|
<a class="xref" href="impala_show.html#show_functions">SHOW FUNCTIONS Statement</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title9" id="show_tables">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title9">SHOW TABLES Statement</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
Displays the names of tables. By default, lists tables in the current database, or with the
|
|
<code class="ph codeph">IN</code> clause, in a specified database. By default, lists all tables, or with the
|
|
<code class="ph codeph">LIKE</code> clause, only those whose name match a pattern with <code class="ph codeph">*</code> wildcards.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The user ID that the <span class="keyword cmdname">impalad</span> daemon runs under,
|
|
typically the <code class="ph codeph">impala</code> user, must have read and execute
|
|
permissions for all directories that are part of the table.
|
|
(A table could span multiple different HDFS directories if it is partitioned.
|
|
The directories could be widely scattered because a partition can reside
|
|
in an arbitrary HDFS directory based on its <code class="ph codeph">LOCATION</code> attribute.)
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The following examples demonstrate the <code class="ph codeph">SHOW TABLES</code> statement.
|
|
If the database contains no tables, the result set is empty.
|
|
If the database does contain tables, <code class="ph codeph">SHOW TABLES IN <var class="keyword varname">db_name</var></code>
|
|
lists all the table names. <code class="ph codeph">SHOW TABLES</code> with no qualifiers lists
|
|
all the table names in the current database.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>create database empty_db;
|
|
show tables in empty_db;
|
|
Fetched 0 row(s) in 0.11s
|
|
|
|
create database full_db;
|
|
create table full_db.t1 (x int);
|
|
create table full_db.t2 like full_db.t1;
|
|
|
|
show tables in full_db;
|
|
+------+
|
|
| name |
|
|
+------+
|
|
| t1 |
|
|
| t2 |
|
|
+------+
|
|
|
|
use full_db;
|
|
show tables;
|
|
+------+
|
|
| name |
|
|
+------+
|
|
| t1 |
|
|
| t2 |
|
|
+------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
This example demonstrates how <code class="ph codeph">SHOW TABLES LIKE '<var class="keyword varname">wildcard_pattern</var>'</code>
|
|
lists table names that match a pattern, or multiple alternative patterns.
|
|
The ability to do wildcard matches for table names makes it helpful to establish naming conventions for tables to
|
|
conveniently locate a group of related tables.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>create table fact_tbl (x int);
|
|
create table dim_tbl_1 (s string);
|
|
create table dim_tbl_2 (s string);
|
|
|
|
/* Asterisk is the wildcard character. Only 2 out of the 3 just-created tables are returned. */
|
|
show tables like 'dim*';
|
|
+-----------+
|
|
| name |
|
|
+-----------+
|
|
| dim_tbl_1 |
|
|
| dim_tbl_2 |
|
|
+-----------+
|
|
|
|
/* We are already in the FULL_DB database, but just to be sure we can specify the database name also. */
|
|
show tables in full_db like 'dim*';
|
|
+-----------+
|
|
| name |
|
|
+-----------+
|
|
| dim_tbl_1 |
|
|
| dim_tbl_2 |
|
|
+-----------+
|
|
|
|
/* The pipe character separates multiple wildcard patterns. */
|
|
show tables like '*dim*|t*';
|
|
+-----------+
|
|
| name |
|
|
+-----------+
|
|
| dim_tbl_1 |
|
|
| dim_tbl_2 |
|
|
| t1 |
|
|
| t2 |
|
|
+-----------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_tables.html#tables">Overview of Impala Tables</a>, <a class="xref" href="impala_create_table.html#create_table">CREATE TABLE Statement</a>,
|
|
<a class="xref" href="impala_alter_table.html#alter_table">ALTER TABLE Statement</a>, <a class="xref" href="impala_drop_table.html#drop_table">DROP TABLE Statement</a>,
|
|
<a class="xref" href="impala_describe.html#describe">DESCRIBE Statement</a>, <a class="xref" href="impala_show.html#show_create_table">SHOW CREATE TABLE Statement</a>,
|
|
<a class="xref" href="impala_show.html#show_table_stats">SHOW TABLE STATS Statement</a>,
|
|
<a class="xref" href="impala_show.html#show_databases">SHOW DATABASES</a>,
|
|
<a class="xref" href="impala_show.html#show_functions">SHOW FUNCTIONS Statement</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title10" id="show_create_table">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title10">SHOW CREATE TABLE Statement</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
As a schema changes over time, you might run a <code class="ph codeph">CREATE TABLE</code> statement followed by several
|
|
<code class="ph codeph">ALTER TABLE</code> statements. To capture the cumulative effect of all those statements,
|
|
<code class="ph codeph">SHOW CREATE TABLE</code> displays a <code class="ph codeph">CREATE TABLE</code> statement that would reproduce
|
|
the current structure of a table. You can use this output in scripts that set up or clone a group of
|
|
tables, rather than trying to reproduce the original sequence of <code class="ph codeph">CREATE TABLE</code> and
|
|
<code class="ph codeph">ALTER TABLE</code> statements. When creating variations on the original table, or cloning the
|
|
original table on a different system, you might need to edit the <code class="ph codeph">SHOW CREATE TABLE</code> output
|
|
to change things such as the database name, <code class="ph codeph">LOCATION</code> field, and so on that might be
|
|
different on the destination system.
|
|
</p>
|
|
|
|
<p class="p">
|
|
If you specify a view name in the <code class="ph codeph">SHOW CREATE TABLE</code>,
|
|
it returns a <code class="ph codeph">CREATE VIEW</code> statement with column names
|
|
and the original SQL statement to reproduce the view. You need the
|
|
<code class="ph codeph">VIEW_METADATA</code> privilege on the view and
|
|
<code class="ph codeph">SELECT</code> privilege on all underlying views and tables to
|
|
successfully run the <code class="ph codeph">SHOW CREATE VIEW</code> statement for a
|
|
view. The <code class="ph codeph">SHOW CREATE VIEW</code> is available as an alias for
|
|
<code class="ph codeph">SHOW CREATE TABLE</code>.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
For Kudu tables:
|
|
</p>
|
|
|
|
|
|
<ul class="ul">
|
|
<li class="li">
|
|
<p class="p">
|
|
The column specifications include attributes such as <code class="ph codeph">NULL</code>,
|
|
<code class="ph codeph">NOT NULL</code>, <code class="ph codeph">ENCODING</code>, and <code class="ph codeph">COMPRESSION</code>.
|
|
If you do not specify those attributes in the original <code class="ph codeph">CREATE TABLE</code> statement,
|
|
the <code class="ph codeph">SHOW CREATE TABLE</code> output displays the defaults that were used.
|
|
</p>
|
|
|
|
</li>
|
|
|
|
<li class="li">
|
|
<p class="p">
|
|
The specifications of any <code class="ph codeph">RANGE</code> clauses are not displayed in full.
|
|
To see the definition of the range clauses for a Kudu table, use the <code class="ph codeph">SHOW RANGE PARTITIONS</code> statement.
|
|
</p>
|
|
|
|
</li>
|
|
|
|
<li class="li">
|
|
<p class="p">
|
|
The <code class="ph codeph">TBLPROPERTIES</code> output reflects the Kudu master address
|
|
and the internal Kudu name associated with the Impala table.
|
|
</p>
|
|
|
|
</li>
|
|
|
|
</ul>
|
|
|
|
|
|
<pre class="pre codeblock"><code>
|
|
show CREATE TABLE numeric_grades_default_letter;
|
|
+------------------------------------------------------------------------------------------------+
|
|
| result |
|
|
+------------------------------------------------------------------------------------------------+
|
|
| CREATE TABLE user.numeric_grades_default_letter ( |
|
|
| score TINYINT NOT NULL ENCODING AUTO_ENCODING COMPRESSION DEFAULT_COMPRESSION, |
|
|
| letter_grade STRING NULL ENCODING AUTO_ENCODING COMPRESSION DEFAULT_COMPRESSION DEFAULT '-', |
|
|
| student STRING NULL ENCODING AUTO_ENCODING COMPRESSION DEFAULT_COMPRESSION, |
|
|
| PRIMARY KEY (score) |
|
|
| ) |
|
|
| PARTITION BY RANGE (score) (...) . |
|
|
| STORED AS KUDU |
|
|
| TBLPROPERTIES ('kudu.master_addresses'='vd0342.example.com:7051') |
|
|
+------------------------------------------------------------------------------------------------+
|
|
|
|
show range partitions numeric_grades_default_letter;
|
|
+--------------------------+
|
|
| RANGE (score) |
|
|
+--------------------------+
|
|
| 0 <= VALUES < 50 |
|
|
| 50 <= VALUES < 65 |
|
|
| 65 <= VALUES < 80 |
|
|
| 80 <= VALUES < 100 |
|
|
+--------------------------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The following example shows how various clauses from the <code class="ph codeph">CREATE TABLE</code> statement are
|
|
represented in the output of <code class="ph codeph">SHOW CREATE TABLE</code>.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>create table show_create_table_demo (id int comment "Unique ID", y double, s string)
|
|
partitioned by (year smallint)
|
|
stored as parquet;
|
|
|
|
show create table show_create_table_demo;
|
|
+----------------------------------------------------------------------------------------+
|
|
| result |
|
|
+----------------------------------------------------------------------------------------+
|
|
| CREATE TABLE scratch.show_create_table_demo ( |
|
|
| id INT COMMENT 'Unique ID', |
|
|
| y DOUBLE, |
|
|
| s STRING |
|
|
| ) |
|
|
| PARTITIONED BY ( |
|
|
| year SMALLINT |
|
|
| ) |
|
|
| STORED AS PARQUET |
|
|
| LOCATION 'hdfs://127.0.0.1:8020/user/hive/warehouse/scratch.db/show_create_table_demo' |
|
|
| TBLPROPERTIES ('transient_lastDdlTime'='1418152582') |
|
|
+----------------------------------------------------------------------------------------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
The following example shows how, after a sequence of <code class="ph codeph">ALTER TABLE</code> statements, the output
|
|
from <code class="ph codeph">SHOW CREATE TABLE</code> represents the current state of the table. This output could be
|
|
used to create a matching table rather than executing the original <code class="ph codeph">CREATE TABLE</code> and
|
|
sequence of <code class="ph codeph">ALTER TABLE</code> statements.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>alter table show_create_table_demo drop column s;
|
|
alter table show_create_table_demo set fileformat textfile;
|
|
|
|
show create table show_create_table_demo;
|
|
+----------------------------------------------------------------------------------------+
|
|
| result |
|
|
+----------------------------------------------------------------------------------------+
|
|
| CREATE TABLE scratch.show_create_table_demo ( |
|
|
| id INT COMMENT 'Unique ID', |
|
|
| y DOUBLE |
|
|
| ) |
|
|
| PARTITIONED BY ( |
|
|
| year SMALLINT |
|
|
| ) |
|
|
| STORED AS TEXTFILE |
|
|
| LOCATION 'hdfs://127.0.0.1:8020/user/hive/warehouse/demo.db/show_create_table_demo' |
|
|
| TBLPROPERTIES ('transient_lastDdlTime'='1418152638') |
|
|
+----------------------------------------------------------------------------------------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_create_table.html#create_table">CREATE TABLE Statement</a>, <a class="xref" href="impala_describe.html#describe">DESCRIBE Statement</a>,
|
|
<a class="xref" href="impala_show.html#show_tables">SHOW TABLES Statement</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title11" id="show_create_view">
|
|
<h2 class="title topictitle2" id="ariaid-title11">SHOW CREATE VIEW Statement</h2>
|
|
|
|
<div class="body conbody">
|
|
<p class="p"> The <code class="ph codeph">SHOW CREATE VIEW</code>, it returns a <code class="ph codeph">CREATE
|
|
VIEW</code> statement with column names and the original SQL
|
|
statement to reproduce the view. You need the
|
|
<code class="ph codeph">VIEW_METADATA</code> privilege on the view and
|
|
<code class="ph codeph">SELECT</code> privilege on all underlying views and tables to
|
|
successfully run the <code class="ph codeph">SHOW CREATE VIEW</code> statement for a
|
|
view. </p>
|
|
|
|
<p class="p">
|
|
The <code class="ph codeph">SHOW CREATE VIEW</code> is an alias for <code class="ph codeph">SHOW
|
|
CREATE TABLE</code>.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title12" id="show_table_stats">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title12">SHOW TABLE STATS Statement</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
The <code class="ph codeph">SHOW TABLE STATS</code> and <code class="ph codeph">SHOW COLUMN STATS</code> variants are important for
|
|
tuning performance and diagnosing performance issues, especially with the largest tables and the most
|
|
complex join queries.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
Any values that are not available (because the <code class="ph codeph">COMPUTE STATS</code> statement has not been run
|
|
yet) are displayed as <code class="ph codeph">-1</code>.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<code class="ph codeph">SHOW TABLE STATS</code> provides some general information about the table, such as the number of
|
|
files, overall size of the data, whether some or all of the data is in the HDFS cache, and the file format,
|
|
that is useful whether or not you have run the <code class="ph codeph">COMPUTE STATS</code> statement. A
|
|
<code class="ph codeph">-1</code> in the <code class="ph codeph">#Rows</code> output column indicates that the <code class="ph codeph">COMPUTE
|
|
STATS</code> statement has never been run for this table. If the table is partitioned, <code class="ph codeph">SHOW TABLE
|
|
STATS</code> provides this information for each partition. (It produces the same output as the
|
|
<code class="ph codeph">SHOW PARTITIONS</code> statement in this case.)
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The output of <code class="ph codeph">SHOW COLUMN STATS</code> is primarily only useful after the <code class="ph codeph">COMPUTE
|
|
STATS</code> statement has been run on the table. A <code class="ph codeph">-1</code> in the <code class="ph codeph">#Distinct
|
|
Values</code> output column indicates that the <code class="ph codeph">COMPUTE STATS</code> statement has never been
|
|
run for this table. Currently, Impala always leaves the <code class="ph codeph">#Nulls</code> column as
|
|
<code class="ph codeph">-1</code>, even after <code class="ph codeph">COMPUTE STATS</code> has been run.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
These <code class="ph codeph">SHOW</code> statements work on actual tables only, not on views.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Kudu considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
Because Kudu tables do not have characteristics derived from HDFS, such
|
|
as number of files and HDFS cache status, the output of
|
|
<code class="ph codeph">SHOW TABLE STATS</code> reflects different characteristics
|
|
that apply to Kudu tables.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>
|
|
show table stats kudu_table;
|
|
+-------+-------------+---------+--------+------------------------------+
|
|
| #Rows | #Partitions | Size | Format | Location |
|
|
+-------+-------------+---------+--------+------------------------------+
|
|
| 100 | 7 | 56.16MB | KUDU | kudu-master.example.com:7051 |
|
|
+-------+-------------+---------+--------+------------------------------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The following examples show how the <code class="ph codeph">SHOW TABLE STATS</code> statement displays physical
|
|
information about a table and the associated data files:
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>show table stats store_sales;
|
|
+-------+--------+----------+--------------+--------+-------------------+------------------------------------+-----------+
|
|
| #Rows | #Files | Size | Bytes Cached | Format | Incremental stats | Location | EC Policy |
|
|
+-------+--------+----------+--------------+--------+-------------------+------------------------------------+-----------+
|
|
| -1 | 1 | 370.45MB | NOT CACHED | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/store_sales | NONE |
|
|
+-------+--------+----------+--------------+--------+-------------------+------------------------------------+-----------+
|
|
|
|
show table stats customer;
|
|
+-------+--------+---------+--------------+--------+-------------------+---------------------------------+-----------+
|
|
| #Rows | #Files | Size | Bytes Cached | Format | Incremental stats | Location | EC Policy |
|
|
+-------+--------+---------+--------------+--------+-------------------+---------------------------------+-----------+
|
|
| -1 | 1 | 12.60MB | NOT CACHED | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/customer | NONE |
|
|
+-------+--------+---------+--------------+--------+-------------------+---------------------------------+-----------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
The following example shows how, after a <code class="ph codeph">COMPUTE STATS</code> or <code class="ph codeph">COMPUTE INCREMENTAL
|
|
STATS</code> statement, the <code class="ph codeph">#Rows</code> field is now filled in. Because the
|
|
<code class="ph codeph">STORE_SALES</code> table in this example is not partitioned, the <code class="ph codeph">COMPUTE INCREMENTAL
|
|
STATS</code> statement produces regular stats rather than incremental stats, therefore the
|
|
<code class="ph codeph">Incremental stats</code> field remains <code class="ph codeph">false</code>.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>compute stats customer;
|
|
+------------------------------------------+
|
|
| summary |
|
|
+------------------------------------------+
|
|
| Updated 1 partition(s) and 18 column(s). |
|
|
+------------------------------------------+
|
|
|
|
show table stats customer;
|
|
+--------+--------+---------+--------------+--------+-------------------+---------------------------------+-----------+
|
|
| #Rows | #Files | Size | Bytes Cached | Format | Incremental stats | Location | EC Policy |
|
|
+--------+--------+---------+--------------+--------+-------------------+---------------------------------+-----------+
|
|
| 100000 | 1 | 12.60MB | NOT CACHED | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/customer | NONE |
|
|
+--------+--------+---------+--------------+--------+-------------------+---------------------------------+-----------+
|
|
|
|
compute incremental stats store_sales;
|
|
+------------------------------------------+
|
|
| summary |
|
|
+------------------------------------------+
|
|
| Updated 1 partition(s) and 23 column(s). |
|
|
+------------------------------------------+
|
|
|
|
show table stats store_sales;
|
|
+---------+--------+----------+--------------+--------+-------------------+------------------------------------+-----------+
|
|
| #Rows | #Files | Size | Bytes Cached | Format | Incremental stats | Location | EC Policy |
|
|
+---------+--------+----------+--------------+--------+-------------------+------------------------------------+-----------+
|
|
| 2880404 | 1 | 370.45MB | NOT CACHED | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/store_sales | NONE |
|
|
+---------+--------+----------+--------------+--------+-------------------+------------------------------------+-----------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong>
|
|
</p>
|
|
|
|
<p class="p">
|
|
The user ID that the <span class="keyword cmdname">impalad</span> daemon runs under,
|
|
typically the <code class="ph codeph">impala</code> user, must have read and execute
|
|
permissions for all directories that are part of the table.
|
|
(A table could span multiple different HDFS directories if it is partitioned.
|
|
The directories could be widely scattered because a partition can reside
|
|
in an arbitrary HDFS directory based on its <code class="ph codeph">LOCATION</code> attribute.)
|
|
The Impala user must also have execute
|
|
permission for the database directory, and any parent directories of the database directory in HDFS.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_compute_stats.html#compute_stats">COMPUTE STATS Statement</a>, <a class="xref" href="impala_show.html#show_column_stats">SHOW COLUMN STATS Statement</a>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
See <a class="xref" href="impala_perf_stats.html#perf_stats">Table and Column Statistics</a> for usage information and examples.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title13" id="show_column_stats">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title13">SHOW COLUMN STATS Statement</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
The <code class="ph codeph">SHOW TABLE STATS</code> and <code class="ph codeph">SHOW COLUMN STATS</code> variants are important for
|
|
tuning performance and diagnosing performance issues, especially with the largest tables and the most
|
|
complex join queries.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The output for <code class="ph codeph">SHOW COLUMN STATS</code> includes
|
|
the relevant information for Kudu tables.
|
|
The information for column statistics that originates in the
|
|
underlying Kudu storage layer is also represented in the
|
|
metastore database that Impala uses.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The following examples show the output of the <code class="ph codeph">SHOW COLUMN STATS</code> statement for some tables,
|
|
before the <code class="ph codeph">COMPUTE STATS</code> statement is run. Impala deduces some information, such as
|
|
maximum and average size for fixed-length columns, and leaves and unknown values as <code class="ph codeph">-1</code>.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>show column stats customer;
|
|
+------------------------+--------+------------------+--------+----------+----------+
|
|
| Column | Type | #Distinct Values | #Nulls | Max Size | Avg Size |
|
|
+------------------------+--------+------------------+--------+----------+----------+
|
|
| c_customer_sk | INT | -1 | -1 | 4 | 4 |
|
|
| c_customer_id | STRING | -1 | -1 | -1 | -1 |
|
|
| c_current_cdemo_sk | INT | -1 | -1 | 4 | 4 |
|
|
| c_current_hdemo_sk | INT | -1 | -1 | 4 | 4 |
|
|
| c_current_addr_sk | INT | -1 | -1 | 4 | 4 |
|
|
| c_first_shipto_date_sk | INT | -1 | -1 | 4 | 4 |
|
|
| c_first_sales_date_sk | INT | -1 | -1 | 4 | 4 |
|
|
| c_salutation | STRING | -1 | -1 | -1 | -1 |
|
|
| c_first_name | STRING | -1 | -1 | -1 | -1 |
|
|
| c_last_name | STRING | -1 | -1 | -1 | -1 |
|
|
| c_preferred_cust_flag | STRING | -1 | -1 | -1 | -1 |
|
|
| c_birth_day | INT | -1 | -1 | 4 | 4 |
|
|
| c_birth_month | INT | -1 | -1 | 4 | 4 |
|
|
| c_birth_year | INT | -1 | -1 | 4 | 4 |
|
|
| c_birth_country | STRING | -1 | -1 | -1 | -1 |
|
|
| c_login | STRING | -1 | -1 | -1 | -1 |
|
|
| c_email_address | STRING | -1 | -1 | -1 | -1 |
|
|
| c_last_review_date_sk | STRING | -1 | -1 | -1 | -1 |
|
|
+------------------------+--------+------------------+--------+----------+----------+
|
|
|
|
show column stats store_sales;
|
|
+-----------------------+-------+------------------+--------+----------+----------+
|
|
| Column | Type | #Distinct Values | #Nulls | Max Size | Avg Size |
|
|
+-----------------------+-------+------------------+--------+----------+----------+
|
|
| ss_sold_date_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_sold_time_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_item_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_customer_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_cdemo_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_hdemo_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_addr_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_store_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_promo_sk | INT | -1 | -1 | 4 | 4 |
|
|
| ss_ticket_number | INT | -1 | -1 | 4 | 4 |
|
|
| ss_quantity | INT | -1 | -1 | 4 | 4 |
|
|
| ss_wholesale_cost | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_list_price | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_sales_price | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_ext_discount_amt | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_ext_sales_price | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_ext_wholesale_cost | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_ext_list_price | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_ext_tax | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_coupon_amt | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_net_paid | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_net_paid_inc_tax | FLOAT | -1 | -1 | 4 | 4 |
|
|
| ss_net_profit | FLOAT | -1 | -1 | 4 | 4 |
|
|
+-----------------------+-------+------------------+--------+----------+----------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
The following examples show the output of the <code class="ph codeph">SHOW COLUMN STATS</code> statement for some tables,
|
|
after the <code class="ph codeph">COMPUTE STATS</code> statement is run. Now most of the <code class="ph codeph">-1</code> values are
|
|
changed to reflect the actual table data. The <code class="ph codeph">#Nulls</code> column remains <code class="ph codeph">-1</code>
|
|
because Impala does not use the number of <code class="ph codeph">NULL</code> values to influence query planning.
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>compute stats customer;
|
|
+------------------------------------------+
|
|
| summary |
|
|
+------------------------------------------+
|
|
| Updated 1 partition(s) and 18 column(s). |
|
|
+------------------------------------------+
|
|
|
|
compute stats store_sales;
|
|
+------------------------------------------+
|
|
| summary |
|
|
+------------------------------------------+
|
|
| Updated 1 partition(s) and 23 column(s). |
|
|
+------------------------------------------+
|
|
|
|
show column stats customer;
|
|
+------------------------+--------+------------------+--------+----------+--------+
|
|
| Column | Type | #Distinct Values | #Nulls | Max Size | Avg Size
|
|
+------------------------+--------+------------------+--------+----------+--------+
|
|
| c_customer_sk | INT | 139017 | -1 | 4 | 4 |
|
|
| c_customer_id | STRING | 111904 | -1 | 16 | 16 |
|
|
| c_current_cdemo_sk | INT | 95837 | -1 | 4 | 4 |
|
|
| c_current_hdemo_sk | INT | 8097 | -1 | 4 | 4 |
|
|
| c_current_addr_sk | INT | 57334 | -1 | 4 | 4 |
|
|
| c_first_shipto_date_sk | INT | 4374 | -1 | 4 | 4 |
|
|
| c_first_sales_date_sk | INT | 4409 | -1 | 4 | 4 |
|
|
| c_salutation | STRING | 7 | -1 | 4 | 3.1308 |
|
|
| c_first_name | STRING | 3887 | -1 | 11 | 5.6356 |
|
|
| c_last_name | STRING | 4739 | -1 | 13 | 5.9106 |
|
|
| c_preferred_cust_flag | STRING | 3 | -1 | 1 | 0.9656 |
|
|
| c_birth_day | INT | 31 | -1 | 4 | 4 |
|
|
| c_birth_month | INT | 12 | -1 | 4 | 4 |
|
|
| c_birth_year | INT | 71 | -1 | 4 | 4 |
|
|
| c_birth_country | STRING | 205 | -1 | 20 | 8.4001 |
|
|
| c_login | STRING | 1 | -1 | 0 | 0 |
|
|
| c_email_address | STRING | 94492 | -1 | 46 | 26.485 |
|
|
| c_last_review_date_sk | STRING | 349 | -1 | 7 | 6.7561 |
|
|
+------------------------+--------+------------------+--------+----------+--------+
|
|
|
|
show column stats store_sales;
|
|
+-----------------------+-------+------------------+--------+----------+----------+
|
|
| Column | Type | #Distinct Values | #Nulls | Max Size | Avg Size |
|
|
+-----------------------+-------+------------------+--------+----------+----------+
|
|
| ss_sold_date_sk | INT | 4395 | -1 | 4 | 4 |
|
|
| ss_sold_time_sk | INT | 63617 | -1 | 4 | 4 |
|
|
| ss_item_sk | INT | 19463 | -1 | 4 | 4 |
|
|
| ss_customer_sk | INT | 122720 | -1 | 4 | 4 |
|
|
| ss_cdemo_sk | INT | 242982 | -1 | 4 | 4 |
|
|
| ss_hdemo_sk | INT | 8097 | -1 | 4 | 4 |
|
|
| ss_addr_sk | INT | 70770 | -1 | 4 | 4 |
|
|
| ss_store_sk | INT | 6 | -1 | 4 | 4 |
|
|
| ss_promo_sk | INT | 355 | -1 | 4 | 4 |
|
|
| ss_ticket_number | INT | 304098 | -1 | 4 | 4 |
|
|
| ss_quantity | INT | 105 | -1 | 4 | 4 |
|
|
| ss_wholesale_cost | FLOAT | 9600 | -1 | 4 | 4 |
|
|
| ss_list_price | FLOAT | 22191 | -1 | 4 | 4 |
|
|
| ss_sales_price | FLOAT | 20693 | -1 | 4 | 4 |
|
|
| ss_ext_discount_amt | FLOAT | 228141 | -1 | 4 | 4 |
|
|
| ss_ext_sales_price | FLOAT | 433550 | -1 | 4 | 4 |
|
|
| ss_ext_wholesale_cost | FLOAT | 406291 | -1 | 4 | 4 |
|
|
| ss_ext_list_price | FLOAT | 574871 | -1 | 4 | 4 |
|
|
| ss_ext_tax | FLOAT | 91806 | -1 | 4 | 4 |
|
|
| ss_coupon_amt | FLOAT | 228141 | -1 | 4 | 4 |
|
|
| ss_net_paid | FLOAT | 493107 | -1 | 4 | 4 |
|
|
| ss_net_paid_inc_tax | FLOAT | 653523 | -1 | 4 | 4 |
|
|
| ss_net_profit | FLOAT | 611934 | -1 | 4 | 4 |
|
|
+-----------------------+-------+------------------+--------+----------+----------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong>
|
|
</p>
|
|
|
|
<p class="p">
|
|
The user ID that the <span class="keyword cmdname">impalad</span> daemon runs under,
|
|
typically the <code class="ph codeph">impala</code> user, must have read and execute
|
|
permissions for all directories that are part of the table.
|
|
(A table could span multiple different HDFS directories if it is partitioned.
|
|
The directories could be widely scattered because a partition can reside
|
|
in an arbitrary HDFS directory based on its <code class="ph codeph">LOCATION</code> attribute.)
|
|
The Impala user must also have execute
|
|
permission for the database directory, and any parent directories of the database directory in HDFS.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_compute_stats.html#compute_stats">COMPUTE STATS Statement</a>, <a class="xref" href="impala_show.html#show_table_stats">SHOW TABLE STATS Statement</a>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
See <a class="xref" href="impala_perf_stats.html#perf_stats">Table and Column Statistics</a> for usage information and examples.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title14" id="show_partitions">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title14">SHOW PARTITIONS Statement</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
<code class="ph codeph">SHOW PARTITIONS</code> displays information about each partition for a partitioned table. (The
|
|
output is the same as the <code class="ph codeph">SHOW TABLE STATS</code> statement, but <code class="ph codeph">SHOW PARTITIONS</code>
|
|
only works on a partitioned table.) Because it displays table statistics for all partitions, the output is
|
|
more informative if you have run the <code class="ph codeph">COMPUTE STATS</code> statement after creating all the
|
|
partitions. See <a class="xref" href="impala_compute_stats.html#compute_stats">COMPUTE STATS Statement</a> for details. For example, on a
|
|
<code class="ph codeph">CENSUS</code> table partitioned on the <code class="ph codeph">YEAR</code> column:
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Kudu considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The optional <code class="ph codeph">RANGE</code> clause only applies to Kudu tables. It displays only the partitions
|
|
defined by the <code class="ph codeph">RANGE</code> clause of <code class="ph codeph">CREATE TABLE</code> or <code class="ph codeph">ALTER TABLE</code>.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
Although you can specify <code class="ph codeph"><</code> or
|
|
<code class="ph codeph"><=</code> comparison operators when defining
|
|
range partitions for Kudu tables, Kudu rewrites them if necessary
|
|
to represent each range as
|
|
<code class="ph codeph"><var class="keyword varname">low_bound</var> <= VALUES < <var class="keyword varname">high_bound</var></code>.
|
|
This rewriting might involve incrementing one of the boundary values
|
|
or appending a <code class="ph codeph">\0</code> for string values, so that the
|
|
partition covers the same range as originally specified.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The following example shows the output for a Parquet, text, or other
|
|
HDFS-backed table partitioned on the <code class="ph codeph">YEAR</code> column:
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>[localhost:21000] > show partitions census;
|
|
+-------+-------+--------+------+---------+-------------------+-----------------------------------------+-----------+
|
|
| year | #Rows | #Files | Size | Format | Incremental stats | Location | EC Policy |
|
|
+-------+-------+--------+------+---------+-------------------+-----------------------------------------+-----------+
|
|
| 2000 | -1 | 0 | 0B | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/census/year=2000 | NONE |
|
|
| 2004 | -1 | 0 | 0B | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/census/year=2000 | NONE |
|
|
| 2008 | -1 | 0 | 0B | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/census/year=2000 | NONE |
|
|
| 2010 | -1 | 0 | 0B | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/census/year=2000 | NONE |
|
|
| 2011 | 4 | 1 | 22B | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/census/year=2000 | NONE |
|
|
| 2012 | 4 | 1 | 22B | TEXT | false | hdfs://<var class="keyword varname">impala_data_dir</var>/census/year=2000 | NONE |
|
|
| 2013 | 1 | 1 | 231B | PARQUET | false | hdfs://<var class="keyword varname">impala_data_dir</var>/census/year=2000 | NONE |
|
|
| Total | 9 | 3 | 275B | | | | |
|
|
+-------+-------+--------+------+---------+-------------------+-----------------------------------------+-----------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
The following example shows the output for a Kudu table using the hash
|
|
partitioning mechanism. The number of rows in the result set corresponds to the
|
|
values used in the <code class="ph codeph">PARTITIONS <var class="keyword varname">N</var></code> clause of
|
|
<code class="ph codeph">CREATE TABLE</code>. If the Kudu table is created with the clause
|
|
<code class="ph codeph">PARTITIONS 20</code>, then the result set of
|
|
<code class="ph codeph">SHOW PARTITIONS</code> consists of 20 rows, each representing one of
|
|
the numbered partitions. For example:
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>
|
|
show partitions million_rows_hash;
|
|
|
|
+--------+-----------+----------+-----------------------+------------+
|
|
| # Rows | Start Key | Stop Key | Leader Replica | # Replicas |
|
|
+--------+-----------+----------+-----------------------+------------+
|
|
| -1 | | 00000001 | n236.example.com:7050 | 3 |
|
|
| -1 | 00000001 | 00000002 | n236.example.com:7050 | 3 |
|
|
| -1 | 00000002 | 00000003 | n336.example.com:7050 | 3 |
|
|
| -1 | 00000003 | 00000004 | n238.example.com:7050 | 3 |
|
|
| -1 | 00000004 | 00000005 | n338.example.com:7050 | 3 |
|
|
...
|
|
| -1 | 0000002E | 0000002F | n240.example.com:7050 | 3 |
|
|
| -1 | 0000002F | 00000030 | n336.example.com:7050 | 3 |
|
|
| -1 | 00000030 | 00000031 | n240.example.com:7050 | 3 |
|
|
| -1 | 00000031 | | n334.example.com:7050 | 3 |
|
|
+--------+-----------+----------+-----------------------+------------+
|
|
Fetched 50 row(s) in 0.05s
|
|
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
Impala only computes the number of rows for the whole Kudu table, partition level
|
|
row counts are not available.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
The following example shows the output for a Kudu table
|
|
using the range partitioning mechanism:
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>
|
|
show range partitions million_rows_range;
|
|
+-----------------------+
|
|
| RANGE (id) |
|
|
+-----------------------+
|
|
| VALUES < "A" |
|
|
| "A" <= VALUES < "[" |
|
|
| "a" <= VALUES < "{" |
|
|
| "{" <= VALUES < "~\0" |
|
|
+-----------------------+
|
|
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong>
|
|
</p>
|
|
|
|
<p class="p">
|
|
The user ID that the <span class="keyword cmdname">impalad</span> daemon runs under,
|
|
typically the <code class="ph codeph">impala</code> user, must have read and execute
|
|
permissions for all directories that are part of the table.
|
|
(A table could span multiple different HDFS directories if it is partitioned.
|
|
The directories could be widely scattered because a partition can reside
|
|
in an arbitrary HDFS directory based on its <code class="ph codeph">LOCATION</code> attribute.)
|
|
The Impala user must also have execute
|
|
permission for the database directory, and any parent directories of the database directory in HDFS.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
See <a class="xref" href="impala_perf_stats.html#perf_stats">Table and Column Statistics</a> for usage information and examples.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_show.html#show_table_stats">SHOW TABLE STATS Statement</a>, <a class="xref" href="impala_partitioning.html#partitioning">Partitioning for Impala Tables</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
<div class="topic concept nested1" aria-labelledby="ariaid-title15" id="show_functions">
|
|
|
|
<h2 class="title topictitle2" id="ariaid-title15">SHOW FUNCTIONS Statement</h2>
|
|
|
|
|
|
|
|
<div class="body conbody">
|
|
|
|
<p class="p">
|
|
By default, <code class="ph codeph">SHOW FUNCTIONS</code> displays user-defined functions (UDFs) and <code class="ph codeph">SHOW
|
|
AGGREGATE FUNCTIONS</code> displays user-defined aggregate functions (UDAFs) associated with a particular
|
|
database. The output from <code class="ph codeph">SHOW FUNCTIONS</code> includes the argument signature of each function.
|
|
You specify this argument signature as part of the <code class="ph codeph">DROP FUNCTION</code> statement. You might have
|
|
several UDFs with the same name, each accepting different argument data types.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Usage notes:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
In <span class="keyword">Impala 2.5</span> and higher, the <code class="ph codeph">SHOW FUNCTIONS</code> output includes
|
|
a new column, labelled <code class="ph codeph">is persistent</code>. This property is <code class="ph codeph">true</code> for
|
|
Impala built-in functions, C++ UDFs, and Java UDFs created using the new <code class="ph codeph">CREATE FUNCTION</code>
|
|
syntax with no signature. It is <code class="ph codeph">false</code> for Java UDFs created using the old
|
|
<code class="ph codeph">CREATE FUNCTION</code> syntax that includes the types for the arguments and return value.
|
|
Any functions with <code class="ph codeph">false</code> shown for this property must be created again by the
|
|
<code class="ph codeph">CREATE FUNCTION</code> statement each time the Impala catalog server is restarted.
|
|
See <code class="ph codeph">CREATE FUNCTION</code> for information on switching to the new syntax, so that
|
|
Java UDFs are preserved across restarts. Java UDFs that are persisted this way are also easier
|
|
to share across Impala and Hive.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Security considerations:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
When authorization is enabled, the output of the <code class="ph codeph">SHOW</code> statement only
|
|
shows those objects for which you have the privilege to view. If you believe an object
|
|
exists but you cannot see it in the <code class="ph codeph">SHOW</code> output, check with the system
|
|
administrator if you need to be granted a new privilege for that object. See
|
|
<a class="xref" href="../shared/../topics/impala_authorization.html#authorization">Impala Authorization</a> for how to set up
|
|
authorization and add privileges for specific objects.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">HDFS permissions:</strong> This statement does not touch any HDFS files or directories,
|
|
therefore no HDFS permissions are required.
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Examples:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
To display Impala built-in functions, specify the special database name <code class="ph codeph">_impala_builtins</code>:
|
|
</p>
|
|
|
|
|
|
<pre class="pre codeblock"><code>show functions in _impala_builtins;
|
|
+--------------+-------------------------------------------------+-------------+---------------+
|
|
| return type | signature | binary type | is persistent |
|
|
+--------------+-------------------------------------------------+-------------+---------------+
|
|
| BIGINT | abs(BIGINT) | BUILTIN | true |
|
|
| DECIMAL(*,*) | abs(DECIMAL(*,*)) | BUILTIN | true |
|
|
| DOUBLE | abs(DOUBLE) | BUILTIN | true |
|
|
| FLOAT | abs(FLOAT) | BUILTIN | true |
|
|
+----------------+-----------------------------------------------+-------------+---------------+
|
|
|
|
show functions in _impala_builtins like '*week*';
|
|
+-------------+------------------------------+-------------+---------------+
|
|
| return type | signature | binary type | is persistent |
|
|
+-------------+------------------------------+-------------+---------------+
|
|
| INT | dayofweek(TIMESTAMP) | BUILTIN | true |
|
|
| INT | weekofyear(TIMESTAMP) | BUILTIN | true |
|
|
| TIMESTAMP | weeks_add(TIMESTAMP, BIGINT) | BUILTIN | true |
|
|
| TIMESTAMP | weeks_add(TIMESTAMP, INT) | BUILTIN | true |
|
|
| TIMESTAMP | weeks_sub(TIMESTAMP, BIGINT) | BUILTIN | true |
|
|
| TIMESTAMP | weeks_sub(TIMESTAMP, INT) | BUILTIN | true |
|
|
+-------------+------------------------------+-------------+---------------+
|
|
</code></pre>
|
|
|
|
<p class="p">
|
|
<strong class="ph b">Related information:</strong>
|
|
</p>
|
|
|
|
|
|
<p class="p">
|
|
<a class="xref" href="impala_functions_overview.html#functions">Overview of Impala Functions</a>, <a class="xref" href="impala_functions.html#builtins">Impala Built-In Functions</a>,
|
|
<a class="xref" href="impala_udf.html#udfs">User-Defined Functions (UDFs)</a>,
|
|
<a class="xref" href="impala_show.html#show_databases">SHOW DATABASES</a>,
|
|
<a class="xref" href="impala_show.html#show_tables">SHOW TABLES Statement</a>
|
|
</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
|
|
|
|
</body>
|
|
</html> |