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---
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layout: global
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title: ANALYZE TABLE
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displayTitle: ANALYZE TABLE
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license: |
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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---
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2019-09-03 18:26:12 -04:00
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### Description
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The `ANALYZE TABLE` statement collects statistics about the table to be used by the query optimizer to find a better query execution plan.
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### Syntax
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{% highlight sql %}
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ANALYZE TABLE table_identifier [ partition_spec ]
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COMPUTE STATISTICS [ NOSCAN | FOR COLUMNS col [ , ... ] | FOR ALL COLUMNS ]
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{% endhighlight %}
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### Parameters
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<dl>
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<dt><code><em>table_identifier</em></code></dt>
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<dd>
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Specifies a table name, which may be optionally qualified with a database name.<br><br>
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<b>Syntax:</b>
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<code>
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[ database_name. ] table_name
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</code>
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</dd>
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</dl>
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<dl>
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<dt><code><em>partition_spec</em></code></dt>
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<dd>
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An optional parameter that specifies a comma separated list of key and value pairs
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for partitions. When specified, partition statistics is returned.<br><br>
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<b>Syntax:</b>
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<code>
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PARTITION ( partition_col_name [ = partition_col_val ] [ , ... ] )
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</code>
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</dd>
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</dl>
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<dl>
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<dt><code><em>[ NOSCAN | FOR COLUMNS col [ , ... ] | FOR ALL COLUMNS ]</em></code></dt>
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<dd>
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<ul>
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<li> If no analyze option is specified, <code>ANALYZE TABLE</code> collects the table's number of rows and size in bytes. </li>
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<li> <b>NOSCAN</b>
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<br> Collect only the table's size in bytes ( which does not require scanning the entire table ). </li>
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<li> <b>FOR COLUMNS col [ , ... ] <code> | </code> FOR ALL COLUMNS</b>
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<br> Collect column statistics for each column specified, or alternatively for every column, as well as table statistics.
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</li>
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</ul>
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</dd>
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</dl>
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### Examples
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{% highlight sql %}
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ANALYZE TABLE students COMPUTE STATISTICS NOSCAN;
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DESC EXTENDED students;
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......
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Statistics 2820 bytes
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......
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ANALYZE TABLE students COMPUTE STATISTICS;
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DESC EXTENDED students;
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......
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Statistics 2820 bytes, 3 rows
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......
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ANALYZE TABLE students PARTITION (student_id = 111111) COMPUTE STATISTICS;
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DESC EXTENDED students PARTITION (student_id = 111111);
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......
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Partition Statistics 919 bytes, 1 rows
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......
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ANALYZE TABLE students COMPUTE STATISTICS FOR COLUMNS name;
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DESC EXTENDED students name;
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=default tbl=students
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col_name name
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data_type string
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comment NULL
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min NULL
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max NULL
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num_nulls 0
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distinct_count 3
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avg_col_len 11
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max_col_len 13
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histogram NULL
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2020-02-16 10:55:03 -05:00
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{% endhighlight %}
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