From 56f2887dc8ab8d98e0c6a53db01ffb20cde19aa9 Mon Sep 17 00:00:00 2001 From: Huaxin Gao Date: Tue, 3 Sep 2019 15:26:12 -0700 Subject: [PATCH] [SPARK-28788][DOC][SQL] Document ANALYZE TABLE statement in SQL Reference ### 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 Signed-off-by: Xiao Li --- docs/sql-ref-syntax-aux-analyze-table.md | 76 +++++++++++++++++++++++- docs/sql-ref-syntax-aux-analyze.md | 13 ++-- 2 files changed, 80 insertions(+), 9 deletions(-) diff --git a/docs/sql-ref-syntax-aux-analyze-table.md b/docs/sql-ref-syntax-aux-analyze-table.md index e23098903e886..887f225f89bcc 100644 --- a/docs/sql-ref-syntax-aux-analyze-table.md +++ b/docs/sql-ref-syntax-aux-analyze-table.md @@ -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 +
+
table_name
+
The name of an existing table.
+
+ +
+
PARTITION ( partition_col_name [ = partition_col_val ] [ , ... ] )
+
Specifies one or more partition column and value pairs. The partition value is optional.
+
+ +
+
[ NOSCAN | FOR COLUMNS col [ , ... ] | FOR ALL COLUMNS ]
+
+
    +
  • If no analyze option is specified, ANALYZE TABLE collects the table's number of rows and size in bytes.
    • +
  • NOSCAN +
    Collect only the table's size in bytes ( which does not require scanning the entire table ).
    • +
  • FOR COLUMNS col [ , ... ] | FOR ALL COLUMNS +
    Collect column statistics for each column specified, or alternatively for every column, as well as table statistics. +
    • +
+
+
+ +### 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 %} \ No newline at end of file diff --git a/docs/sql-ref-syntax-aux-analyze.md b/docs/sql-ref-syntax-aux-analyze.md index eb0e73d00e848..2d19d18b42527 100644 --- a/docs/sql-ref-syntax-aux-analyze.md +++ b/docs/sql-ref-syntax-aux-analyze.md @@ -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)