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spark-instrumented-optimizer/docs/sql-ref-syntax-aux-analyze-tables.md
Yuming Wang d07fc3076b [SPARK-33687][SQL] Support analyze all tables in a specific database 
### What changes were proposed in this pull request?

This pr add support analyze all tables in a specific database:
```g4
 ANALYZE TABLES ((FROM | IN) multipartIdentifier)? COMPUTE STATISTICS (identifier)?
```

### Why are the changes needed?

1. Make it easy to analyze all tables in a specific database.
2. PostgreSQL has a similar implementation: https://www.postgresql.org/docs/12/sql-analyze.html.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

The feature tested by unit test.
The documentation tested by regenerating the documentation:

menu-sql.yaml |  sql-ref-syntax-aux-analyze-tables.md
-- | --
![image](https://user-images.githubusercontent.com/5399861/109098769-dc33a200-775c-11eb-86b1-55531e5425e0.png) | ![image](https://user-images.githubusercontent.com/5399861/109098841-02594200-775d-11eb-8588-de8da97ec94a.png)

Closes #30648 from wangyum/SPARK-33687.

Authored-by: Yuming Wang <yumwang@ebay.com>
Signed-off-by: Takeshi Yamamuro <yamamuro@apache.org>
2021-03-01 09:06:47 +09:00

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layout title displayTitle license
global ANALYZE TABLES ANALYZE TABLES Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. 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. See the License for the specific language governing permissions and limitations under the License.

Description

The ANALYZE TABLES statement collects statistics about all the tables in a specified database to be used by the query optimizer to find a better query execution plan.

Syntax

ANALYZE TABLES [ { FROM | IN } database_name ] COMPUTE STATISTICS [ NOSCAN ]

Parameters

  • { FROM | IN } database_name

    Specifies the name of the database to be analyzed. Without a database name, ANALYZE collects all tables in the current database that the current user has permission to analyze.

  • [ NOSCAN ]

    Collects only the table's size in bytes (which does not require scanning the entire table).

Examples

CREATE DATABASE school_db;
USE school_db;

CREATE TABLE teachers (name STRING, teacher_id INT);
INSERT INTO teachers VALUES ('Tom', 1), ('Jerry', 2);

CREATE TABLE students (name STRING, student_id INT, age SHORT);
INSERT INTO students VALUES ('Mark', 111111, 10), ('John', 222222, 11);

ANALYZE TABLES IN school_db COMPUTE STATISTICS NOSCAN;

DESC EXTENDED teachers;
+--------------------+--------------------+-------+
|            col_name|           data_type|comment|
+--------------------+--------------------+-------+
|                name|              string|   null|
|          teacher_id|                 int|   null|
|                 ...|                 ...|    ...|
|            Provider|             parquet|       |
|          Statistics|          1382 bytes|       |
|                 ...|                 ...|    ...|
+--------------------+--------------------+-------+

DESC EXTENDED students;
+--------------------+--------------------+-------+
|            col_name|           data_type|comment|
+--------------------+--------------------+-------+
|                name|              string|   null|
|          student_id|                 int|   null|
|                 age|            smallint|   null|
|                 ...|                 ...|    ...|
|          Statistics|          1828 bytes|       |
|                 ...|                 ...|    ...|
+--------------------+--------------------+-------+

ANALYZE TABLES COMPUTE STATISTICS;

DESC EXTENDED teachers;
+--------------------+--------------------+-------+
|            col_name|           data_type|comment|
+--------------------+--------------------+-------+
|                name|              string|   null|
|          teacher_id|                 int|   null|
|                 ...|                 ...|    ...|
|            Provider|             parquet|       |
|          Statistics|  1382 bytes, 2 rows|       |
|                 ...|                 ...|    ...|
+--------------------+--------------------+-------+

DESC EXTENDED students;
+--------------------+--------------------+-------+
|            col_name|           data_type|comment|
+--------------------+--------------------+-------+
|                name|              string|   null|
|          student_id|                 int|   null|
|                 age|            smallint|   null|
|                 ...|                 ...|    ...|
|            Provider|             parquet|       |
|          Statistics|  1828 bytes, 2 rows|       |
|                 ...|                 ...|    ...|
+--------------------+--------------------+-------+

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