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[SPARK-28788][DOC][SQL] Document ANALYZE TABLE statement in SQL Reference

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### What changes were proposed in this pull request?
Document ANALYZE TABLE statement in SQL Reference

### Why are the changes needed?
To complete SQL reference

### Does this PR introduce any user-facing change?
Yes

***Before***:
There was no documentation for this.

***After***:
![image](https://user-images.githubusercontent.com/13592258/64046883-f8339480-cb21-11e9-85da-6617d5c96412.png)

![image](https://user-images.githubusercontent.com/13592258/64209526-9a6eb780-ce55-11e9-9004-53c5c5d24567.png)

![image](https://user-images.githubusercontent.com/13592258/64209542-a2c6f280-ce55-11e9-8624-e7349204ec8e.png)

### How was this patch tested?
Tested using jykyll build --serve

Closes #25524 from huaxingao/spark-28788.

Authored-by: Huaxin Gao <huaxing@us.ibm.com>
Signed-off-by: Xiao Li <gatorsmile@gmail.com>
This commit is contained in:
Huaxin Gao 2019-09-03 15:26:12 -07:00 committed by Xiao Li
parent 89800931aa
commit 56f2887dc8
2 changed files with 80 additions and 9 deletions
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76
docs/sql-ref-syntax-aux-analyze-table.md
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@ -19,4 +19,78 @@ license: |
limitations under the License.
---
**This page is under construction**
### Description
The `ANALYZE TABLE` statement collects statistics about the table to be used by the query optimizer to find a better query execution plan.
### Syntax
{% highlight sql %}
ANALYZE TABLE table_name [ PARTITION ( partition_col_name [ = partition_col_val ] [ , ... ] ) ]
COMPUTE STATISTICS [ NOSCAN | FOR COLUMNS col [ , ... ] | FOR ALL COLUMNS ]
{% endhighlight %}
### Parameters
<dl>
<dt><code><em>table_name</em></code></dt>
<dd>The name of an existing table.</dd>
</dl>
<dl>
<dt><code><em>PARTITION ( partition_col_name [ = partition_col_val ] [ , ... ] )</em></code></dt>
<dd>Specifies one or more partition column and value pairs. The partition value is optional.</dd>
</dl>
<dl>
<dt><code><em>[ NOSCAN | FOR COLUMNS col [ , ... ] | FOR ALL COLUMNS ]</em></code></dt>
<dd>
<ul>
<li> If no analyze option is specified, <code>ANALYZE TABLE</code> collects the table's number of rows and size in bytes. </li>
<li> <b>NOSCAN</b>
<br> Collect only the table's size in bytes ( which does not require scanning the entire table ). </li>
<li> <b>FOR COLUMNS col [ , ... ] <code> | </code> FOR ALL COLUMNS</b>
<br> Collect column statistics for each column specified, or alternatively for every column, as well as table statistics.
</li>
</ul>
</dd>
</dl>
### Examples
{% highlight sql %}
ANALYZE TABLE students COMPUTE STATISTICS NOSCAN;
DESC EXTENDED students;
......
Statistics 2820 bytes
......
ANALYZE TABLE students COMPUTE STATISTICS;
DESC EXTENDED students;
......
Statistics 2820 bytes, 3 rows
......
ANALYZE TABLE students PARTITION (student_id = 111111) COMPUTE STATISTICS;
DESC EXTENDED students PARTITION (student_id = 111111);
......
Partition Statistics 919 bytes, 1 rows
......
ANALYZE TABLE students COMPUTE STATISTICS FOR COLUMNS name;
DESC EXTENDED students name;
=default tbl=students
col_name name
data_type string
comment NULL
min NULL
max NULL
num_nulls 0
distinct_count 3
avg_col_len 11
max_col_len 13
histogram NULL
{% endhighlight %}

13
docs/sql-ref-syntax-aux-analyze.md
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@ -1,7 +1,7 @@
---
layout: global
title: Reference
displayTitle: Reference
title: ANALYZE
displayTitle: ANALYZE
license: |
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
@ -9,9 +9,9 @@ license: |
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@ -19,7 +19,4 @@ license: |
limitations under the License.
---
Spark SQL is a Apache Spark's module for working with structured data.
This guide is a reference for Structured Query Language (SQL) for Apache
Spark. This document describes the SQL constructs supported by Spark in detail
along with usage examples when applicable.
* [ANALYZE TABLE statement](sql-ref-syntax-aux-analyze-table.html)