亚洲国产日韩欧美一区二区三区,精品亚洲国产成人av在线,国产99视频精品免视看7,99国产精品久久久久久久成人热,欧美日韩亚洲国产综合乱

Table of Contents
How to tame those slow SQL: The Secret of Slow Query Logs
Home Database Mysql Tutorial How to locate SQL performance bottlenecks through slow query logs?

How to locate SQL performance bottlenecks through slow query logs?

Apr 08, 2025 am 10:09 AM
mysql tool Solution Slow query log sql optimization sql statement SQL performance bottleneck

The main steps to optimize SQL using slow query logs: 1. Turn on the slow query log and set the execution time threshold (for example, modify the my.cnf file in MySQL); 2. Analyze the slow query log and pay attention to execution time, SQL statements and additional information (such as execution plan); 3. Find performance bottlenecks based on the log information, such as missing indexes; 4. Take optimization measures, such as adding indexes (CREATE INDEX statements) or optimizing the SQL statement itself; 5. Combining database monitoring tools and comprehensive analysis of business logic, continuously monitor and optimize database performance. Ultimately, we will achieve the goal of improving database efficiency.

How to locate SQL performance bottlenecks through slow query logs?

How to tame those slow SQL: The Secret of Slow Query Logs

Have you ever been tortured by inefficient database queries? That feeling was as mad as watching a snail crawl. Don't worry, you are not alone! This article will uncover the mystery of slow query logs, teaching you how to use it to scoop up the culprits of slowing down the database and ultimately rejuvenate your database. After reading this article, you will be able to analyze slow queries independently and master the skills to optimize SQL.

Let's start with the basics. Slow query logs, as the name suggests, record SQL statements whose execution time exceeds a certain threshold. You can set this threshold according to the actual situation, such as 1 second, or longer. It is like a database's "black box recorder", faithfully recording every "slow motion" of the database running. By understanding this, you will understand its value: it can accurately tell you which SQL statements need to be optimized.

The way to enable the slow query log varies from database system to database system. Taking MySQL as an example, you need to modify the configuration file my.cnf, add or modify the long_query_time parameter to set the threshold, and enable the slow_query_log parameter. This part of the content is explained in detail in the official MySQL documentation, so I won't go into details. Remember, after the configuration is completed, you need to restart the database service before it takes effect. Don't forget to check the location of the log files, otherwise you will not find the log files and all efforts will be in vain.

Now, let's explore in-depth the "connotation" of slow query logs. A typical slow query log entry usually contains execution time, SQL statements, and some additional information such as execution plan, etc. This information is crucial and they can help you analyze the performance bottlenecks of your query.

Let's look at an example: Suppose such a record appears in your slow query log:

 <code class="sql"># Time: 2024-03-08T10:00:00.000000</code><h1> User@Host: root[root] @ localhost []</h1><h1> Query_time: 2.500000 Lock_time: 0.000000 Rows_sent: 1000 Rows_examined: 1000000</h1><p> SELECT <em>FROM users WHERE last_login <p>This record shows that the execution time of this SQL statement reached 2.5 seconds, and 1 million rows of data were scanned to find 1,000 records that met the criteria. This is obviously a performance bottleneck. What's the problem? It is very likely that the index is missing. The <code>last_login</code> field should be indexed. </p>
<p>The solution is simple: add an index. In MySQL, you can use the <code>CREATE INDEX</code> statement to add an index: </p>
<pre class="brush:php;toolbar:false"> <code class="sql">CREATE INDEX idx_last_login ON users (last_login);</code> 

After adding the index, the database can quickly locate data that meets the conditions, thereby greatly improving query efficiency. Remember, although indexes can increase query speed, they will also increase the burden of write operations. Therefore, you need to be cautious when adding indexes and weigh the pros and cons according to actual situations. Blindly adding indexes will backfire.

In addition to adding indexes, there are other optimization methods, such as optimizing the query statement itself, avoiding the use of SELECT

, choosing the appropriate connection method, etc. These methods need to be analyzed in combination with specific SQL statements and database structure. Proficient in SQL optimization techniques requires a lot of practice and experience accumulation.

Lastly, I want to emphasize that slow query logs are just a tool to diagnose SQL performance issues and they don't solve all problems by themselves. You need to combine database monitoring tools such as MySQL's Performance Schema, and your business logic to comprehensively analyze it to find the most effective solution. Remember that continuous monitoring and optimizing database performance is a long-term process that requires you to continue to learn and practice. Don’t be afraid of trying or failing. Only by constantly exploring can you become an expert in database performance optimization!

The above is the detailed content of How to locate SQL performance bottlenecks through slow query logs?. 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

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
1488
72
How to check the main trends of beginners in the currency circle How to check the main trends of beginners in the currency circle Jul 31, 2025 pm 09:45 PM

Identifying the trend of the main capital can significantly improve the quality of investment decisions. Its core value lies in trend prediction, support/pressure position verification and sector rotation precursor; 1. Track the net inflow direction, trading ratio imbalance and market price order cluster through large-scale transaction data; 2. Use the on-chain giant whale address to analyze position changes, exchange inflows and position costs; 3. Capture derivative market signals such as futures open contracts, long-short position ratios and liquidated risk zones; in actual combat, trends are confirmed according to the four-step method: technical resonance, exchange flow, derivative indicators and market sentiment extreme value; the main force often adopts a three-step harvesting strategy: sweeping and manufacturing FOMO, KOL collaboratively shouting orders, and short-selling backhand shorting; novices should take risk aversion actions: when the main force's net outflow exceeds $15 million, reduce positions by 50%, and large-scale selling orders

Ethereum ETH latest price APP ETH latest price trend chart analysis software Ethereum ETH latest price APP ETH latest price trend chart analysis software Jul 31, 2025 pm 10:27 PM

1. Download and install the application through the official recommended channel to ensure safety; 2. Access the designated download address to complete the file acquisition; 3. Ignore the device safety reminder and complete the installation as prompts; 4. You can refer to the data of mainstream platforms such as Huobi HTX and Ouyi OK for market comparison; the APP provides real-time market tracking, professional charting tools, price warning and market information aggregation functions; when analyzing trends, long-term trend judgment, technical indicator application, trading volume changes and fundamental information; when choosing software, you should pay attention to data authority, interface friendliness and comprehensive functions to improve analysis efficiency and decision-making accuracy.

BTC digital currency account registration tutorial: Complete account opening in three steps BTC digital currency account registration tutorial: Complete account opening in three steps Jul 31, 2025 pm 10:42 PM

First, select well-known platforms such as Binance Binance or Ouyi OKX, and prepare your email and mobile phone number; 1. Visit the official website of the platform and click to register, enter your email or mobile phone number and set a high-strength password; 2. Submit information after agreeing to the terms of service, and complete account activation through the email or mobile phone verification code; 3. Complete identity authentication (KYC) after logging in, enable secondary verification (2FA) and check security settings regularly to ensure account security. After completing the above steps, you can successfully create a BTC digital currency account.

What are the websites for real-time price query of Bitcoin? Recommended websites that can view Bitcoin K-line and depth chart What are the websites for real-time price query of Bitcoin? Recommended websites that can view Bitcoin K-line and depth chart Jul 31, 2025 pm 10:54 PM

In the digital currency market, real-time mastering of Bitcoin prices and transaction in-depth information is a must-have skill for every investor. Viewing accurate K-line charts and depth charts can help judge the power of buying and selling, capture market changes, and improve the scientific nature of investment decisions.

btc trading platform latest version app download 5.0.5 btc trading platform official website APP download link btc trading platform latest version app download 5.0.5 btc trading platform official website APP download link Aug 01, 2025 pm 11:30 PM

1. First, ensure that the device network is stable and has sufficient storage space; 2. Download it through the official download address [adid]fbd7939d674997cdb4692d34de8633c4[/adid]; 3. Complete the installation according to the device prompts, and the official channel is safe and reliable; 4. After the installation is completed, you can experience professional trading services comparable to HTX and Ouyi platforms; the new version 5.0.5 feature highlights include: 1. Optimize the user interface, and the operation is more intuitive and convenient; 2. Improve transaction performance and reduce delays and slippages; 3. Enhance security protection and adopt advanced encryption technology; 4. Add a variety of new technical analysis chart tools; pay attention to: 1. Properly keep the account password to avoid logging in on public devices; 2.

Stablecoin purchasing channel broad spot Stablecoin purchasing channel broad spot Jul 31, 2025 pm 10:30 PM

Binance provides bank transfers, credit cards, P2P and other methods to purchase USDT, USDC and other stablecoins, with fiat currency entrance and high security; 2. Ouyi OKX supports credit cards, bank cards and third-party payment to purchase stablecoins, and provides OTC and P2P transaction services; 3. Sesame Open Gate.io can purchase stablecoins through fiat currency channels and P2P transactions, supporting multiple fiat currency recharges and convenient operation; 4. Huobi provides fiat currency trading area and P2P market to purchase stablecoins, with strict risk control and high-quality customer service; 5. KuCoin supports credit cards and bank transfers to purchase stablecoins, with diverse P2P transactions and friendly interfaces; 6. Kraken supports ACH, SEPA and other bank transfer methods to purchase stablecoins, with high security

USDT virtual currency account activation guide USDT digital asset registration tutorial USDT virtual currency account activation guide USDT digital asset registration tutorial Aug 01, 2025 pm 11:36 PM

First, choose a reputable digital asset platform. 1. Recommend mainstream platforms such as Binance, Ouyi, Huobi, Damen Exchange; 2. Visit the official website and click "Register", use your email or mobile phone number and set a high-strength password; 3. Complete email or mobile phone verification code verification; 4. After logging in, perform identity verification (KYC), submit identity proof documents and complete facial recognition; 5. Enable two-factor identity verification (2FA), set an independent fund password, and regularly check the login record to ensure the security of the account, and finally successfully open and manage the USDT virtual currency account.

USDT virtual currency purchase process USDT transaction detailed complete guide USDT virtual currency purchase process USDT transaction detailed complete guide Aug 01, 2025 pm 11:33 PM

First, choose a reputable trading platform such as Binance, Ouyi, Huobi or Damen Exchange; 1. Register an account and set a strong password; 2. Complete identity verification (KYC) and submit real documents; 3. Select the appropriate merchant to purchase USDT and complete payment through C2C transactions; 4. Enable two-factor identity verification, set a capital password and regularly check account activities to ensure security. The entire process needs to be operated on the official platform to prevent phishing, and finally complete the purchase and security management of USDT.

See all articles