How to avoid slow queries in PHP language development

With the rapid development of the Internet, reliability and efficiency have become one of the most important issues for developers. For PHP language developers, solving slow queries has become one of the common problems. The emergence of slow queries will cause the website to respond slowly, which will affect the user experience and may even lead to data security issues. To this end, this article will introduce how to avoid slow queries in PHP development.

1. What is slow query?

In the MySQL database, the phenomenon that the query speed is slower than expected is called a slow query. Slow queries not only affect the performance of the website, but also affect the performance of the entire database by making query execution time longer. This problem often occurs with large data volumes.

2. Causes of slow queries

There are many reasons for slow queries. The following are the most common ones:

1. Indexes are not used correctly.

2. A large number of degenerate functions are used in query statements, such as: LIKE, ORDER BY, etc.

3. Too many subqueries are used in the query statement.

4. Improper design of database tables.

5. The service load is too high, causing the database response to slow down.

3. Methods to solve slow queries

1. Use indexes correctly.

According to normal logic, the index will speed up the query. If your MySQL data table regularly executes a large number of SELECT statements, you can create indexes to improve query performance. There are some points that need to be noted when creating an index:

1) Choose an appropriate index. It is not recommended to create an index for every column.

2) Don’t over-index.

3) Avoid index conflicts.

4) For smaller tables, it is not suitable to create indexes.

2. Use cache.

For some frequently queried data (such as comments, articles, etc.), the data can be cached on the cache server. This can reduce the number of database queries and reduce the load on the database, thereby improving the response speed of the website. In PHP language development, caching mechanisms such as Redis or Memcache can be used to reduce query requests to MySQL.

3. Optimize query statements.

During development, query statements can be optimized to improve execution efficiency. The following are some basic optimization measures:

1) Limit the size of the result set and use LIMIT instead of SELECT *.

2) Reduce the number of layers of related queries.

3) Reduce the number of fields in the SELECT clause and only query the required columns.

4) Use joins instead of subqueries.

5) Use original series columns instead of function columns as much as possible.

4. Reduce database load.

In PHP development, there are some methods to reduce database load:

1) Increase read and write separation, by separating read and write operations, use the Master database to handle write operations, and the Slave database to handle read operations .

2) Add sub-database and sub-table. For business systems with large amounts of data, balanced storage and query of data can be achieved through sub-database and sub-table.

3) Use caching technology to reduce the load of MySQL through the caching mechanism.

4) Increase data redundancy backup and increase system stability and fault tolerance through a small amount of redundancy backup.

4. Summary

How to avoid slow queries in PHP language development is a complex task. Using appropriate technologies and techniques can reduce the possibility of slow queries. In actual development, you can combine database performance monitoring tools to discover and solve slow query problems in a timely manner. As a PHP developer, you need to constantly optimize and improve your technology, solve problems caused by slow queries through correct methods, and constantly improve your development experience.

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