Most people who are engaged in the search engine industry should have read such a classic book, or at least know about it. I was attracted to this book at the earliest and made it very clear, the train of thought is also coherent, but unfortunately the level is limited and cannot be understood in many places.
Later, I put down this book, went into the search industry, made some projects one after another, read almost all the technical documents of the company, and read a lot of related papers,
As you can see, text compression can be classified into two categories: the symbol method and the dictionary method. The following describes the methods respectively:
1) Symbolic method, symbolwise MethodThe common encoding method is that each
[MySQL Notes] SQL optimization tool-explain the output format of the explain command
If you have experience using MySQL, you may encounter slow SQL queries in your project. In some scenarios, you can easily locate the problem (for example, when a single table operation has slow SQL queries, check the SQL statement carefully and it is usually easy to locate the index problem). In some complex business scenar
EXPLAIN is used to return a row of information for each table in the SELECT statement. Tables are listed in the order they will be read by MySQL during query processing.
EXPLAIN is used to return a row of information for each table in the SELECT statement. Tables are listed in the order they will be read by MySQL during query processing.
The explanation of mysql expl
The explanation of mysql explain is clear.Of
With the help of explain, you will know when to add an index to the table to use the index to search for records so that select can run faster.If the index is not properly used, you can run analyze table to update the statistical information of the table, such as the base of the key, which can help you make better choices in terms of optimization.
The explanation of mysql explain is clear.Of
With the help of explain, you will know when to add an index to the table to use the index to search for records so that select can run faster.If the index is not properly used, you can run analyze table to update the statistical information of the table, such as the base of the key, which can help you make better choices in terms of optimization.
Explain analyzes SQL efficiency and explain SQL Efficiency
The Explain command is the first recommended command for solving database performance. Most performance problems can be solved simply by using this command. The Explain command can be used to view the execution results of SQL statements, it can help you select
Database Tuning tutorial (4) Explain performance analysis command, tuning explain
In the previous chapter, we learned how to find slow queries and record statements into logs. How can we know where statement problems occur after slow queries are found. This chapter describes how to use the database performance analysis commands provided by Mysql to analyze SQL statements.
Ii.
1. EXPLAIN tbl_name
EXPLAIN tbl_name is a synonym for DESCRIBE tbl_name or show columns from tbl_name.
2. EXPLAIN [EXTENDED] SELECT select_options
If the keyword "EXPLAIN" is placed before the SELECT statement, MySQL will EXPLAIN how it processes the SELECT statement and pro
[Learn Python with me] Explain the execution principle in Python and explain the execution principle in python.
The explain Execution here is relative to the compilation execution. We all know that a program written in C/C ++ or another compilation language needs to be converted from the source file to the machine language used by the computer, A binary executabl
[Learn python with me] Explain the execution principle in Python and explain the execution principle in python.
The explain Execution here is relative to the compilation execution. We all know that a program written in C/C ++ or another compilation language needs to be converted from the source file to the machine language used by the computer, A binary executabl
Tags: db2 dbvisualizer explainUse Dbvisulalizer link DB2 to view execution plans as reported errorsExplain tables does not exist. Check the explain plan properties for this database connection.is the execution plan of the table no village, check the execution plan properties.View connection properties as followsThe explain plan attribute is only available in Db2luw, so the datatype in the connection attribu
Explain the application of PHP cache technology in detail, and explain the PHP caching technology
PHP, a recent rise in the web Design scripting language, due to its strong and scalable, in recent years has been a rapid development, PHP compared to the traditional ASP site, in the speed of the absolute advantage, want to MSSQL 60,000 data PHP if 40 seconds, ASP less than 2 minutes. Because of the increasin
Database Tuning tutorial (4) Explain performance analysis command, tuning explain
In the previous chapter, we learned how to find slow queries and record statements into logs. How can we know where statement problems occur after slow queries are found. This chapter describes how to use the database performance analysis commands provided by Mysql to analyze SQL statements.
Ii.
Mysql explain usage (use explain to optimize the query statement), mysqlexplain
First, I will give a simple example and then explain the information in the explain column.
Table 1: catefory document category table:
Create table if not exists 'category '('id' smallint (5) unsigned not null AUTO_INCREMENT, 'name' varchar
EXPLAIN the EXPLAIN command in MySQL (for example, MySQLexplain)
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Explain shows how mysql uses indexes to process select statements and connect tables. It can help you select better indexes and write more optimized query statements.
You can add the explain statement before the select statement:
For example:
JavaScript: this can be used to explain and javascript can be used to explain.
I recently studied JavaScript and read the book "You Don't Know JS". I think this JavaScript is an excellent method, you must check the JavaScript BASICS (not recommended for beginners ). The author has profound knowledge, thorough understanding, smooth writing, classic cases, and exclusive talents.
This article will make a summa
Use sed to explain and use sed to explain
I am a bit confused about this title. This article only describes a problem I encountered in practice, the cause of the problem, and the solution. in addition, experienced people may be able to see the problem at a glance. at least know about debugging and troubleshooting.
Unfortunately, I actually know that debugging takes more than an hour. In many cases, what we
Explain how to create and monitor Oracle scheduled jobs, and explain oraclejob
I. How to Create a scheduled JOB by version)
Method 1: sys. dbms_job.submit () before 10 GB ()
Method 2: sys. Dbms_Scheduler.create_job () after 10 GB ()
Ii. JOB operation monitoring:
If you need to monitor job running before 10 Gb, you need to create a job running log table by yourself, and perform operations on the log table b
Explain the oracle Stored Procedure dynamic SQL statement instance and explain the oracle instance
Note:
In the string''Represents'. For example, 'select ", a from table'
Create or replace procedure partition (card_type in VARCHAR2, card_no in VARCHAR2, start_date in VARCHAR2, end_date in VARCHAR2, interval in VARCHAR2, timed out VARCHAR2, pat_type out VARCHAR2, pat_no VARCHAR2, pat_id out VARCHAR2, pat_ca
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