Shulou(Shulou.com)05/31 Report--

This article mainly explains "the physical file composition of mysql". Interested friends may wish to have a look at it. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "the physical file composition of mysql".

Composition of mysql physical files

1.1 log document

1) error log: Error Log

Records all serious warnings and error messages during the operation of MyQL Server, as well as

Details of each startup and shutdown of MySQLServer. By default, the system logs the error log

The function is turned off.

2) binary log: Binary Log & Binary Log Index

Name] "after the recording function is turned on, MySQL will change all the modified data

The query of the library data is recorded in the log file in binary form. Of course, the log is not limited to query.

The statement is so simple, it also includes the time that each query executes, the resources consumed, and related transaction information.

So binlog is transaction-safe

3) Update log: update log

4) query log: query log

5) slow query log: slow query log

6) online redo log of Innodb: innodb redo log

Innodb is a transaction secure storage engine, and its transaction security is mainly through online redo.

The log and the undo information recorded in the table space are guaranteed. What Innodb does is recorded in the redo log

All physical changes and transaction information, through redo logs and undo information, Innodb guarantees in any situation

Transaction security in the case of.

2.2 data file

In MySQL, each one exists under a defined (or default) data directory with a

A folder named after a database to store various table data files in the database.

1. ".frm" file

Table-related meta information is stored in the ".frm" file, including the definition of the table structure.

Semantic information, etc. Regardless of the storage engine, each table has a ".frm" text named after the table name.

Pieces.

2. ".MYD" file

The ".MYD" file is dedicated to the MyISAM storage engine and stores data from MyISAM tables. Every MyISAM

The table will have a ".MYD" file corresponding to it, which is also stored in the folder of the database to which it belongs.

With the ".frm" file.

3. ".MYI" file

The ".MYI" file is also dedicated to the MyISAM storage engine and mainly stores the index phase of the MyISAM table.

Turn off the information.

4. ".ibd" file and ibdata file

These two kinds of files are files that store Innodb data, and the reason why there are two kinds of files to store Innodb

Data (including indexes) because the way Innodb data is stored can be configured to determine whether to use the

Shared tablespaces store data or exclusive tablespaces store data.

At this point, I believe you have a deeper understanding of the "physical file composition of mysql". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.