国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Home Database Mysql Tutorial mysql Sort aborted: Out of sort memory, consider increasing_MySQL

mysql Sort aborted: Out of sort memory, consider increasing_MySQL

May 27, 2016 pm 01:44 PM
mysql sort

今天在檢查mysql服務(wù)器的時(shí)候提示Sort aborted: Out of sort memory, consider increasing server sort buffer size,安裝字面意思就是 sort內(nèi)存溢出,考慮增加服務(wù)器的排序緩沖區(qū)(sort_buffer_size)大小

sort_buffer_size=3M
join_buffer_size = 3M

下面是針對16G 內(nèi)存設(shè)置的參數(shù):

sort_buffer_size = 2M
# Sort_Buffer_Size 是一個(gè)connection級參數(shù),在每個(gè)connection(session)第一次需要使用這個(gè)buffer的時(shí)候,一次性分配設(shè)置的內(nèi)存。
#Sort_Buffer_Size 并不是越大越好,由于是connection級的參數(shù),過大的設(shè)置+高并發(fā)可能會(huì)耗盡系統(tǒng)內(nèi)存資源。例如:500個(gè)連接將會(huì)消耗 500*sort_buffer_size(8M)=4G內(nèi)存
#Sort_Buffer_Size 超過2KB的時(shí)候,就會(huì)使用mmap() 而不是 malloc() 來進(jìn)行內(nèi)存分配,導(dǎo)致效率降低。
#技術(shù)導(dǎo)讀 http://blog.webshuo.com/2011/02/16/mysql-sort_buffer_size/
#dev-doc: http://dev.mysql.com/doc/refman/5.5/en/server-parameters.html
#explain select*from table where order limit;出現(xiàn)filesort
#屬重點(diǎn)優(yōu)化參數(shù)

代碼如下:


mysqlslap -uroot -h127.0.0.1 -q ' select sql_no_cache * from sbtest order by pad limit 1' -c 100 --create-schema=test -i 10

測試結(jié)果:

執(zhí)行時(shí)間

250K : 1.318s
512K : 1.944s
3M???? : 2.412s

250 K
[root@localhost tmp]# mysqlslap -uroot -h127.0.0.1 -q ' select sql_no_cache * from sbtest order by pad limit 1' -c 100 --create-schema=test -i 10
Benchmark
??????? Average number of seconds to run all queries: 1.318 seconds
??????? Minimum number of seconds to run all queries: 1.285 seconds
??????? Maximum number of seconds to run all queries: 1.378 seconds
??????? Number of clients running queries: 100
??????? Average number of queries per client: 1

512 K

[root@localhost tmp]# mysqlslap -uroot -h127.0.0.1 -q ' select sql_no_cache * from sbtest order by pad limit 1' -c 100 --create-schema=test -i 10
Benchmark
??????? Average number of seconds to run all queries: 1.944 seconds
??????? Minimum number of seconds to run all queries: 1.362 seconds
??????? Maximum number of seconds to run all queries: 4.406 seconds
??????? Number of clients running queries: 100
??????? Average number of queries per client: 1

3M
[root@localhost tmp]# mysqlslap -uroot -h127.0.0.1 -q ' select sql_no_cache * from sbtest order by pad limit 1' -c 100 --create-schema=test -i 10
Benchmark
??????? Average number of seconds to run all queries: 2.412 seconds
??????? Minimum number of seconds to run all queries: 2.376 seconds
??????? Maximum number of seconds to run all queries: 2.527 seconds
??????? Number of clients running queries: 100
??????? Average number of queries per client: 1

結(jié)論:
確實(shí)如文檔所說, 使用mmap 分配內(nèi)存時(shí),會(huì)帶來性能上的損耗,影響大約在 30% 左右。
由于是limit 1,因此減弱了buffer size對排序速度的影響。
其實(shí)buffer size 越大,所需要進(jìn)行的sort-merge的次數(shù)越少,執(zhí)行時(shí)間越短。視具體的語句而定。
我只是想說明下,并不是越大越好。 也并不存在一個(gè)絕對的最佳值。
還是要看具體的業(yè)務(wù)環(huán)境決定值的大小。 對于高并發(fā)的應(yīng)用,還是別設(shè)置太大的比較好。

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

Undress AI Tool

Undress AI Tool

Undress images for free

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.

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

PHP Tutorial
1502
276
How to use PHP to develop a Q&A community platform Detailed explanation of PHP interactive community monetization model How to use PHP to develop a Q&A community platform Detailed explanation of PHP interactive community monetization model Jul 23, 2025 pm 07:21 PM

1. The first choice for the Laravel MySQL Vue/React combination in the PHP development question and answer community is the first choice for Laravel MySQL Vue/React combination, due to its maturity in the ecosystem and high development efficiency; 2. High performance requires dependence on cache (Redis), database optimization, CDN and asynchronous queues; 3. Security must be done with input filtering, CSRF protection, HTTPS, password encryption and permission control; 4. Money optional advertising, member subscription, rewards, commissions, knowledge payment and other models, the core is to match community tone and user needs.

How to set environment variables in PHP environment Description of adding PHP running environment variables How to set environment variables in PHP environment Description of adding PHP running environment variables Jul 25, 2025 pm 08:33 PM

There are three main ways to set environment variables in PHP: 1. Global configuration through php.ini; 2. Passed through a web server (such as SetEnv of Apache or fastcgi_param of Nginx); 3. Use putenv() function in PHP scripts. Among them, php.ini is suitable for global and infrequently changing configurations, web server configuration is suitable for scenarios that need to be isolated, and putenv() is suitable for temporary variables. Persistence policies include configuration files (such as php.ini or web server configuration), .env files are loaded with dotenv library, and dynamic injection of variables in CI/CD processes. Security management sensitive information should be avoided hard-coded, and it is recommended to use.en

Automating MySQL Deployments with Infrastructure as Code Automating MySQL Deployments with Infrastructure as Code Jul 20, 2025 am 01:49 AM

To achieve MySQL deployment automation, the key is to use Terraform to define resources, Ansible management configuration, Git for version control, and strengthen security and permission management. 1. Use Terraform to define MySQL instances, such as the version, type, access control and other resource attributes of AWSRDS; 2. Use AnsiblePlaybook to realize detailed configurations such as database user creation, permission settings, etc.; 3. All configuration files are included in Git management, support change tracking and collaborative development; 4. Avoid hard-coded sensitive information, use Vault or AnsibleVault to manage passwords, and set access control and minimum permission principles.

How to use PHP to develop product recommendation module PHP recommendation algorithm and user behavior analysis How to use PHP to develop product recommendation module PHP recommendation algorithm and user behavior analysis Jul 23, 2025 pm 07:00 PM

To collect user behavior data, you need to record browsing, search, purchase and other information into the database through PHP, and clean and analyze it to explore interest preferences; 2. The selection of recommendation algorithms should be determined based on data characteristics: based on content, collaborative filtering, rules or mixed recommendations; 3. Collaborative filtering can be implemented in PHP to calculate user cosine similarity, select K nearest neighbors, weighted prediction scores and recommend high-scoring products; 4. Performance evaluation uses accuracy, recall, F1 value and CTR, conversion rate and verify the effect through A/B tests; 5. Cold start problems can be alleviated through product attributes, user registration information, popular recommendations and expert evaluations; 6. Performance optimization methods include cached recommendation results, asynchronous processing, distributed computing and SQL query optimization, thereby improving recommendation efficiency and user experience.

Securing MySQL Connections with SSL/TLS Encryption Securing MySQL Connections with SSL/TLS Encryption Jul 21, 2025 am 02:08 AM

Why do I need SSL/TLS encryption MySQL connection? Because unencrypted connections may cause sensitive data to be intercepted, enabling SSL/TLS can prevent man-in-the-middle attacks and meet compliance requirements; 2. How to configure SSL/TLS for MySQL? You need to generate a certificate and a private key, modify the configuration file to specify the ssl-ca, ssl-cert and ssl-key paths and restart the service; 3. How to force SSL when the client connects? Implemented by specifying REQUIRESSL or REQUIREX509 when creating a user; 4. Details that are easily overlooked in SSL configuration include certificate path permissions, certificate expiration issues, and client configuration requirements.

How to build an online customer service robot with PHP. PHP intelligent customer service implementation technology How to build an online customer service robot with PHP. PHP intelligent customer service implementation technology Jul 25, 2025 pm 06:57 PM

PHP plays the role of connector and brain center in intelligent customer service, responsible for connecting front-end input, database storage and external AI services; 2. When implementing it, it is necessary to build a multi-layer architecture: the front-end receives user messages, the PHP back-end preprocesses and routes requests, first matches the local knowledge base, and misses, call external AI services such as OpenAI or Dialogflow to obtain intelligent reply; 3. Session management is written to MySQL and other databases by PHP to ensure context continuity; 4. Integrated AI services need to use Guzzle to send HTTP requests, safely store APIKeys, and do a good job of error handling and response analysis; 5. Database design must include sessions, messages, knowledge bases, and user tables, reasonably build indexes, ensure security and performance, and support robot memory

How to develop AI intelligent form system with PHP PHP intelligent form design and analysis How to develop AI intelligent form system with PHP PHP intelligent form design and analysis Jul 25, 2025 pm 05:54 PM

When choosing a suitable PHP framework, you need to consider comprehensively according to project needs: Laravel is suitable for rapid development and provides EloquentORM and Blade template engines, which are convenient for database operation and dynamic form rendering; Symfony is more flexible and suitable for complex systems; CodeIgniter is lightweight and suitable for simple applications with high performance requirements. 2. To ensure the accuracy of AI models, we need to start with high-quality data training, reasonable selection of evaluation indicators (such as accuracy, recall, F1 value), regular performance evaluation and model tuning, and ensure code quality through unit testing and integration testing, while continuously monitoring the input data to prevent data drift. 3. Many measures are required to protect user privacy: encrypt and store sensitive data (such as AES

How to make PHP container support automatic construction? Continuously integrated CI configuration method of PHP environment How to make PHP container support automatic construction? Continuously integrated CI configuration method of PHP environment Jul 25, 2025 pm 08:54 PM

To enable PHP containers to support automatic construction, the core lies in configuring the continuous integration (CI) process. 1. Use Dockerfile to define the PHP environment, including basic image, extension installation, dependency management and permission settings; 2. Configure CI/CD tools such as GitLabCI, and define the build, test and deployment stages through the .gitlab-ci.yml file to achieve automatic construction, testing and deployment; 3. Integrate test frameworks such as PHPUnit to ensure that tests are automatically run after code changes; 4. Use automated deployment strategies such as Kubernetes to define deployment configuration through the deployment.yaml file; 5. Optimize Dockerfile and adopt multi-stage construction

See all articles