Table of Contents
HIVE-Partitioning Getting Started
hive Partitioning
hive bucketing
Home Backend Development PHP Tutorial Five things you must learn to avoid pitfalls when getting started with HIVE partitions

Five things you must learn to avoid pitfalls when getting started with HIVE partitions

Sep 15, 2018 am 11:11 AM

This article brings you the five major knowledge that you must learn to avoid pitfalls when getting started with HIVE partitioning. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

HIVE-Partitioning Getting Started

hive Partitioning

Concept first:
1: Static partitioning is to divide many files under a directory [File] is classified and stored, and can only be refined to [File], but the content cannot be refined. However, only one category (area) can be specified in one operation;
2: One operation of dynamic partition can be divided according to the specific content of the field. Multi-category (area);
3: The purpose of partitioning is to narrow the query scope and improve the query efficiency of a single table when querying a single table
4: Because the partition is specified on the command line, the mr program is not executed at the bottom of the static partition ( Relatively rigid); dynamic partition executes the mr program and extracts the corresponding fields (relatively smart)

Demo steps:

1. Create a student partition table

95001, Li Yong ,Male,20,CS
95002,Liu Chen,Female,19,IS
95003,Wang Min,Female,22,MA
95004,Zhang Li,Male,19,IS
95005, Liu Gang, male, 18, MA
95006, Sun Qing, male, 23, CS

--分区表创建create table t_students(id int,name string,sex string)
partitioned by (age int,class string)row format delimited fields terminated by ',' ;
Copy after login

After creating, check if it is successful

hive> set hive.cli.print.header=true;hive> select * from t_students;OK
t_students.id   t_students.name t_students.sex  t_students.age  t_students.class
Copy after login

2. Add content
(1) load

--静态分区load data local inpath '/root/logs/students.txt' into table t_students partition (age=19,class='MA');
Copy after login

(2)insert
Insert in Hive is mainly used in combination with select query statements.

--动态分区set hive.exec.dynamic.partition=true;set hive.exec.dynamic.partition.mode=nonstrict;insert overwrite table t_students  partition (age,class) 
select * from t_student;
Copy after login

After execution, check the metadata SDS table and you can see all mapping information
Five things you must learn to avoid pitfalls when getting started with HIVE partitions

--使用同样的数据,再次追加insert一次数据
hive> insert into table t_students  partition (age,class) select * from t_student;
Copy after login

After appending data again, the metadata SDS table information remains unchanged, and the files under each partition path become two copies
Five things you must learn to avoid pitfalls when getting started with HIVE partitions

hive bucketing

Bucketing is a more fine-grained division of relative partitions. Bucketing divides the entire data content into buckets based on the hash value of a certain column attribute. If you want to divide the name attribute into three buckets, you need to modulate the hash value of the name attribute value by 3, and divide the data into buckets according to the modulo result. For example, data records with a modulo result of 0 are stored in a file, data with a modulo value of 1 are stored in a file, and data records with a modulo value of 2 are stored in a file.
Note:
First, before bucketing, execute the command hive.enforce.bucketiong=true;
Second, use the keyword clustered by to specify the column name on which the partition is based, and also specify how many to divide into. Bucket, specified here is divided into 3 buckets.
Third, unlike partitioning, partitioning is not based on the columns in the real data table file, but on the pseudo columns we specify, but bucketing is based on the real columns in the data table instead of pseudo columns. Therefore, when specifying the column on which partitioning is based, you must specify the column type, because this column does not exist in the data table file, which is equivalent to creating a new column. Bucketing is based on a column that already exists in the table. The data type of this column is obviously known, so there is no need to specify the column type.

The above is the detailed content of Five things you must learn to avoid pitfalls when getting started with HIVE partitions. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Java Tutorial
1655
14
PHP Tutorial
1252
29
C# Tutorial
1225
24
PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian Dec 24, 2024 pm 04:42 PM

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Explain JSON Web Tokens (JWT) and their use case in PHP APIs. Apr 05, 2025 am 12:04 AM

JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

How do you parse and process HTML/XML in PHP? How do you parse and process HTML/XML in PHP? Feb 07, 2025 am 11:57 AM

This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an

Explain late static binding in PHP (static::). Explain late static binding in PHP (static::). Apr 03, 2025 am 12:04 AM

Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.

PHP Program to Count Vowels in a String PHP Program to Count Vowels in a String Feb 07, 2025 pm 12:12 PM

A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total

PHP and Python: Comparing Two Popular Programming Languages PHP and Python: Comparing Two Popular Programming Languages Apr 14, 2025 am 12:13 AM

PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.

What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases? Apr 03, 2025 am 12:03 AM

What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.

PHP: A Key Language for Web Development PHP: A Key Language for Web Development Apr 13, 2025 am 12:08 AM

PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7

See all articles