关于分表的问题-PHP Tutorial-php.cn

Home

Backend Development

PHP Tutorial

关于分表的问题

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jun 20, 2016 pm 12:59 PM

我现在数据库中有三个表单数据都超过了500万数据,其中有个表超过1000千万,现在查询速度越来越慢

请教高手以下几个问题

1.将超过100万的表就进行分表.

2.如果B数据表拆分100万的表有十个,那么A表中的ID在B表有5条数据，保存在B数据表拆分的10个表中（问题出来了，在读取数据时，不可能去读去B表中所有的表，这5条数据可能放在拆分的第5与第6个表中，如果这样我们只里要读取B表的第5个表与第6个表就行了。前提是我们根本不知道数据在那）。

回复讨论(解决方案)

关注下，最多碰过200W的数据，加索引后很见效，想了解下经过优化的单表数据上限最好是多少条

如果是普通的查询语句几百万条加了索引查询速度没问题的，但连表或子查询就比较慢了

横向分表需要知道目标ID的位置，不然会起反作用效率更慢。
看看能不能按你的外键算法进行分表

分表是有条件的，并非简单的按记录顺序切断
比如你的 A 和 B 是按 id 关联的，那么 B 就要按 A.id 拆分
这样在已知 A.id 的情况下，按拆分规则就可推算出相关的记录会出现在哪些 Bn 中

如果你的表间存在多对多的关系，那么分表就没有意义了
此时应使用过渡表保存关联关系，查询时要分两步走，而不是一次关联所有表
由于过渡表一般只有2列，虽然记录数很多，但一次性加载到内存的可能性很大（就算是需要多次加载，但每次可加载的记录数也很多）

Statement

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

The Continued Use of PHP: Reasons for Its EnduranceApr 19, 2025 am 12:23 AM

What’s still popular is the ease of use, flexibility and a strong ecosystem. 1) Ease of use and simple syntax make it the first choice for beginners. 2) Closely integrated with web development, excellent interaction with HTTP requests and database. 3) The huge ecosystem provides a wealth of tools and libraries. 4) Active community and open source nature adapts them to new needs and technology trends.

PHP and Python: Exploring Their Similarities and DifferencesApr 19, 2025 am 12:21 AM

PHP and Python are both high-level programming languages that are widely used in web development, data processing and automation tasks. 1.PHP is often used to build dynamic websites and content management systems, while Python is often used to build web frameworks and data science. 2.PHP uses echo to output content, Python uses print. 3. Both support object-oriented programming, but the syntax and keywords are different. 4. PHP supports weak type conversion, while Python is more stringent. 5. PHP performance optimization includes using OPcache and asynchronous programming, while Python uses cProfile and asynchronous programming.

PHP and Python: Different Paradigms ExplainedApr 18, 2025 am 12:26 AM

PHP is mainly procedural programming, but also supports object-oriented programming (OOP); Python supports a variety of paradigms, including OOP, functional and procedural programming. PHP is suitable for web development, and Python is suitable for a variety of applications such as data analysis and machine learning.

PHP and Python: A Deep Dive into Their HistoryApr 18, 2025 am 12:25 AM

PHP originated in 1994 and was developed by RasmusLerdorf. It was originally used to track website visitors and gradually evolved into a server-side scripting language and was widely used in web development. Python was developed by Guidovan Rossum in the late 1980s and was first released in 1991. It emphasizes code readability and simplicity, and is suitable for scientific computing, data analysis and other fields.

Choosing Between PHP and Python: A GuideApr 18, 2025 am 12:24 AM

PHP is suitable for web development and rapid prototyping, and Python is suitable for data science and machine learning. 1.PHP is used for dynamic web development, with simple syntax and suitable for rapid development. 2. Python has concise syntax, is suitable for multiple fields, and has a strong library ecosystem.

PHP and Frameworks: Modernizing the LanguageApr 18, 2025 am 12:14 AM

PHP remains important in the modernization process because it supports a large number of websites and applications and adapts to development needs through frameworks. 1.PHP7 improves performance and introduces new features. 2. Modern frameworks such as Laravel, Symfony and CodeIgniter simplify development and improve code quality. 3. Performance optimization and best practices further improve application efficiency.

PHP's Impact: Web Development and BeyondApr 18, 2025 am 12:10 AM

PHPhassignificantlyimpactedwebdevelopmentandextendsbeyondit.1)ItpowersmajorplatformslikeWordPressandexcelsindatabaseinteractions.2)PHP'sadaptabilityallowsittoscaleforlargeapplicationsusingframeworkslikeLaravel.3)Beyondweb,PHPisusedincommand-linescrip

How does PHP type hinting work, including scalar types, return types, union types, and nullable types?Apr 17, 2025 am 12:25 AM

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.

See all articles