MySQL 5.7 Reference Manual

Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6


This is the MySQL™ Reference Manual. It documents MySQL 5.7 through 5.7.32, as well as NDB Cluster releases based on version 7.5 of NDB through 5.7.31-ndb-7.5.20, respectively. It may include documentation of features of MySQL versions that have not yet been released. For information about which versions have been released, see the MySQL 5.7 Release Notes .

MySQL 5.7 features.  This manual describes features that are not included in every edition of MySQL 5.7; such features may not be included in the edition of MySQL 5.7 licensed to you. If you have any questions about the features included in your edition of MySQL 5.7, refer to your MySQL 5.7 license agreement or contact your Oracle sales representative.

For notes detailing the changes in each release, see the MySQL 5.7 Release Notes .

For legal information, including licensing information, see the Preface and Legal Notices.

For help with using MySQL, please visit the MySQL Forums , where you can discuss your issues with other MySQL users.

Document generated on: 2020-07-26 (revision: 66783)

Table of Contents

Preface and Legal Notices
1 General Information
1.1 About This Manual
1.2 Typographical and Syntax Conventions
1.3 Overview of the MySQL Database Management System
1.3.1 What is MySQL?
1.3.2 The Main Features of MySQL
1.3.3 History of MySQL
1.4 What Is New in MySQL 5.7
1.5 Server and Status Variables and Options Added, Deprecated, or Removed in MySQL 5.7
1.6 MySQL Information Sources
1.6.1 MySQL Websites
1.6.2 MySQL Community Support at the MySQL Forums
1.6.3 MySQL Enterprise
1.7 How to Report Bugs or Problems
1.8 MySQL Standards Compliance
1.8.1 MySQL Extensions to Standard SQL
1.8.2 MySQL Differences from Standard SQL
1.8.3 How MySQL Deals with Constraints
1.9 Credits
1.9.1 Contributors to MySQL
1.9.2 Documenters and translators
1.9.3 Packages that support MySQL
1.9.4 Tools that were used to create MySQL
1.9.5 Supporters of MySQL
2 Installing and Upgrading MySQL
2.1 General Installation Guidance
2.1.1 Which MySQL Version and Distribution to Install
2.1.2 How to Get MySQL
2.1.3 Verifying Package Integrity Using MD5 Checksums or GnuPG
2.1.4 Installation Layouts
2.1.5 Compiler-Specific Build Characteristics
2.2 Installing MySQL on Unix/Linux Using Generic Binaries
2.3 Installing MySQL on Microsoft Windows
2.3.1 MySQL Installation Layout on Microsoft Windows
2.3.2 Choosing an Installation Package
2.3.3 MySQL Installer for Windows
2.3.4 Installing MySQL on Microsoft Windows Using a noinstall ZIP Archive
2.3.5 Troubleshooting a Microsoft Windows MySQL Server Installation
2.3.6 Windows Postinstallation Procedures
2.3.7 Windows Platform Restrictions
2.4 Installing MySQL on macOS
2.4.1 General Notes on Installing MySQL on macOS
2.4.2 Installing MySQL on macOS Using Native Packages
2.4.3 Installing a MySQL Launch Daemon
2.4.4 Installing and Using the MySQL Preference Pane
2.5 Installing MySQL on Linux
2.5.1 Installing MySQL on Linux Using the MySQL Yum Repository
2.5.2 Replacing a Third-Party Distribution of MySQL Using the MySQL Yum Repository
2.5.3 Installing MySQL on Linux Using the MySQL APT Repository
2.5.4 Installing MySQL on Linux Using the MySQL SLES Repository
2.5.5 Installing MySQL on Linux Using RPM Packages from Oracle
2.5.6 Installing MySQL on Linux Using Debian Packages from Oracle
2.5.7 Deploying MySQL on Linux with Docker
2.5.8 Installing MySQL on Linux from the Native Software Repositories
2.5.9 Installing MySQL on Linux with Juju
2.5.10 Managing MySQL Server with systemd
2.6 Installing MySQL Using Unbreakable Linux Network (ULN)
2.7 Installing MySQL on Solaris
2.7.1 Installing MySQL on Solaris Using a Solaris PKG
2.8 Installing MySQL on FreeBSD
2.9 Installing MySQL from Source
2.9.1 Source Installation Methods
2.9.2 Source Installation Prerequisites
2.9.3 MySQL Layout for Source Installation
2.9.4 Installing MySQL Using a Standard Source Distribution
2.9.5 Installing MySQL Using a Development Source Tree
2.9.6 Configuring SSL Library Support
2.9.7 MySQL Source-Configuration Options
2.9.8 Dealing with Problems Compiling MySQL
2.9.9 MySQL Configuration and Third-Party Tools
2.10 Postinstallation Setup and Testing
2.10.1 Initializing the Data Directory
2.10.2 Starting the Server
2.10.3 Testing the Server
2.10.4 Securing the Initial MySQL Account
2.10.5 Starting and Stopping MySQL Automatically
2.11 Upgrading MySQL
2.11.1 Before You Begin
2.11.2 Upgrade Paths
2.11.3 Changes in MySQL 5.7
2.11.4 Upgrading MySQL Binary or Package-based Installations on Unix/Linux
2.11.5 Upgrading MySQL with the MySQL Yum Repository
2.11.6 Upgrading MySQL with the MySQL APT Repository
2.11.7 Upgrading MySQL with the MySQL SLES Repository
2.11.8 Upgrading MySQL on Windows
2.11.9 Upgrading a Docker Installation of MySQL
2.11.10 Upgrading MySQL with Directly-Downloaded RPM Packages
2.11.11 Upgrade Troubleshooting
2.11.12 Rebuilding or Repairing Tables or Indexes
2.11.13 Copying MySQL Databases to Another Machine
2.12 Downgrading MySQL
2.12.1 Before You Begin
2.12.2 Downgrade Paths
2.12.3 Downgrade Notes
2.12.4 Downgrading Binary and Package-based Installations on Unix/Linux
2.12.5 Downgrade Troubleshooting
2.13 Perl Installation Notes
2.13.1 Installing Perl on Unix
2.13.2 Installing ActiveState Perl on Windows
2.13.3 Problems Using the Perl DBI/DBD Interface
3 Tutorial
3.1 Connecting to and Disconnecting from the Server
3.2 Entering Queries
3.3 Creating and Using a Database
3.3.1 Creating and Selecting a Database
3.3.2 Creating a Table
3.3.3 Loading Data into a Table
3.3.4 Retrieving Information from a Table
3.4 Getting Information About Databases and Tables
3.5 Using mysql in Batch Mode
3.6 Examples of Common Queries
3.6.1 The Maximum Value for a Column
3.6.2 The Row Holding the Maximum of a Certain Column
3.6.3 Maximum of Column per Group
3.6.4 The Rows Holding the Group-wise Maximum of a Certain Column
3.6.5 Using User-Defined Variables
3.6.6 Using Foreign Keys
3.6.7 Searching on Two Keys
3.6.8 Calculating Visits Per Day
3.7 Using MySQL with Apache
4 MySQL Programs
4.1 Overview of MySQL Programs
4.2 Using MySQL Programs
4.2.1 Invoking MySQL Programs
4.2.2 Specifying Program Options
4.2.3 Command Options for Connecting to the Server
4.2.4 Connecting to the MySQL Server Using Command Options
4.2.5 Connection Transport Protocols
4.2.6 Connection Compression Control
4.2.7 Setting Environment Variables
4.3 Server and Server-Startup Programs
4.3.1 mysqld — The MySQL Server
4.3.2 mysqld_safe — MySQL Server Startup Script
4.3.3 mysql.server — MySQL Server Startup Script
4.3.4 mysqld_multi — Manage Multiple MySQL Servers
4.4 Installation-Related Programs
4.4.1 comp_err — Compile MySQL Error Message File
4.4.2 mysql_install_db — Initialize MySQL Data Directory
4.4.3 mysql_plugin — Configure MySQL Server Plugins
4.4.4 mysql_secure_installation — Improve MySQL Installation Security
4.4.5 mysql_ssl_rsa_setup — Create SSL/RSA Files
4.4.6 mysql_tzinfo_to_sql — Load the Time Zone Tables
4.4.7 mysql_upgrade — Check and Upgrade MySQL Tables
4.5 Client Programs
4.5.1 mysql — The MySQL Command-Line Client
4.5.2 mysqladmin — A MySQL Server Administration Program
4.5.3 mysqlcheck — A Table Maintenance Program
4.5.4 mysqldump — A Database Backup Program
4.5.5 mysqlimport — A Data Import Program
4.5.6 mysqlpump — A Database Backup Program
4.5.7 mysqlshow — Display Database, Table, and Column Information
4.5.8 mysqlslap — A Load Emulation Client
4.6 Administrative and Utility Programs
4.6.1 innochecksum — Offline InnoDB File Checksum Utility
4.6.2 myisam_ftdump — Display Full-Text Index information
4.6.3 myisamchk — MyISAM Table-Maintenance Utility
4.6.4 myisamlog — Display MyISAM Log File Contents
4.6.5 myisampack — Generate Compressed, Read-Only MyISAM Tables
4.6.6 mysql_config_editor — MySQL Configuration Utility
4.6.7 mysqlbinlog — Utility for Processing Binary Log Files
4.6.8 mysqldumpslow — Summarize Slow Query Log Files
4.7 Program Development Utilities
4.7.1 mysql_config — Display Options for Compiling Clients
4.7.2 my_print_defaults — Display Options from Option Files
4.7.3 resolve_stack_dump — Resolve Numeric Stack Trace Dump to Symbols
4.8 Miscellaneous Programs
4.8.1 lz4_decompress — Decompress mysqlpump LZ4-Compressed Output
4.8.2 perror — Display MySQL Error Message Information
4.8.3 replace — A String-Replacement Utility
4.8.4 resolveip — Resolve Host name to IP Address or Vice Versa
4.8.5 zlib_decompress — Decompress mysqlpump ZLIB-Compressed Output
4.9 Environment Variables
4.10 Unix Signal Handling in MySQL
5 MySQL Server Administration
5.1 The MySQL Server
5.1.1 Configuring the Server
5.1.2 Server Configuration Defaults
5.1.3 Server Option, System Variable, and Status Variable Reference
5.1.4 Server System Variable Reference
5.1.5 Server Status Variable Reference
5.1.6 Server Command Options
5.1.7 Server System Variables
5.1.8 Using System Variables
5.1.9 Server Status Variables
5.1.10 Server SQL Modes
5.1.11 Connection Management
5.1.12 IPv6 Support
5.1.13 MySQL Server Time Zone Support
5.1.14 Server-Side Help Support
5.1.15 Server Tracking of Client Session State Changes
5.1.16 The Server Shutdown Process
5.2 The MySQL Data Directory
5.3 The mysql System Database
5.4 MySQL Server Logs
5.4.1 Selecting General Query Log and Slow Query Log Output Destinations
5.4.2 The Error Log
5.4.3 The General Query Log
5.4.4 The Binary Log
5.4.5 The Slow Query Log
5.4.6 The DDL Log
5.4.7 Server Log Maintenance
5.5 MySQL Server Plugins
5.5.1 Installing and Uninstalling Plugins
5.5.2 Obtaining Server Plugin Information
5.5.3 MySQL Enterprise Thread Pool
5.5.4 The Rewriter Query Rewrite Plugin
5.5.5 Version Tokens
5.6 MySQL Server User-Defined Functions
5.6.1 User-Defined Function Reference
5.6.2 Installing and Uninstalling User-Defined Functions
5.6.3 Obtaining User-Defined Function Information
5.7 Running Multiple MySQL Instances on One Machine
5.7.1 Setting Up Multiple Data Directories
5.7.2 Running Multiple MySQL Instances on Windows
5.7.3 Running Multiple MySQL Instances on Unix
5.7.4 Using Client Programs in a Multiple-Server Environment
5.8 Tracing mysqld Using DTrace
5.8.1 mysqld DTrace Probe Reference
6 Security
6.1 General Security Issues
6.1.1 Security Guidelines
6.1.2 Keeping Passwords Secure
6.1.3 Making MySQL Secure Against Attackers
6.1.4 Security-Related mysqld Options and Variables
6.1.5 How to Run MySQL as a Normal User
6.1.6 Security Considerations for LOAD DATA LOCAL
6.1.7 Client Programming Security Guidelines
6.2 Access Control and Account Management
6.2.1 Account User Names and Passwords
6.2.2 Privileges Provided by MySQL
6.2.3 Grant Tables
6.2.4 Specifying Account Names
6.2.5 Access Control, Stage 1: Connection Verification
6.2.6 Access Control, Stage 2: Request Verification
6.2.7 Adding Accounts, Assigning Privileges, and Dropping Accounts
6.2.8 Reserved Accounts
6.2.9 When Privilege Changes Take Effect
6.2.10 Assigning Account Passwords
6.2.11 Password Management
6.2.12 Server Handling of Expired Passwords
6.2.13 Pluggable Authentication
6.2.14 Proxy Users
6.2.15 Account Locking
6.2.16 Setting Account Resource Limits
6.2.17 Troubleshooting Problems Connecting to MySQL
6.2.18 SQL-Based Account Activity Auditing
6.3 Using Encrypted Connections
6.3.1 Configuring MySQL to Use Encrypted Connections
6.3.2 Encrypted Connection TLS Protocols and Ciphers
6.3.3 Creating SSL and RSA Certificates and Keys
6.3.4 SSL Library-Dependent Capabilities
6.3.5 Connecting to MySQL Remotely from Windows with SSH
6.4 Security Plugins
6.4.1 Authentication Plugins
6.4.2 The Connection-Control Plugins
6.4.3 The Password Validation Plugin
6.4.4 The MySQL Keyring
6.4.5 MySQL Enterprise Audit
6.4.6 MySQL Enterprise Firewall
6.4.7 MySQL Enterprise Data Masking and De-Identification
6.5 SELinux
6.5.1 Check if SELinux is Enabled
6.5.2 Changing the SELinux Mode
6.5.3 MySQL Server SELinux Policies
6.5.4 SELinux File Context
6.5.5 SELinux TCP Port Context
6.5.6 Troubleshooting SELinux
7 Backup and Recovery
7.1 Backup and Recovery Types
7.2 Database Backup Methods
7.3 Example Backup and Recovery Strategy
7.3.1 Establishing a Backup Policy
7.3.2 Using Backups for Recovery
7.3.3 Backup Strategy Summary
7.4 Using mysqldump for Backups
7.4.1 Dumping Data in SQL Format with mysqldump
7.4.2 Reloading SQL-Format Backups
7.4.3 Dumping Data in Delimited-Text Format with mysqldump
7.4.4 Reloading Delimited-Text Format Backups
7.4.5 mysqldump Tips
7.5 Point-in-Time (Incremental) Recovery
7.5.1 Point-in-Time Recovery Using Binary Log
7.5.2 Point-in-Time Recovery Using Event Positions
7.6 MyISAM Table Maintenance and Crash Recovery
7.6.1 Using myisamchk for Crash Recovery
7.6.2 How to Check MyISAM Tables for Errors
7.6.3 How to Repair MyISAM Tables
7.6.4 MyISAM Table Optimization
7.6.5 Setting Up a MyISAM Table Maintenance Schedule
8 Optimization
8.1 Optimization Overview
8.2 Optimizing SQL Statements
8.2.1 Optimizing SELECT Statements
8.2.2 Optimizing Subqueries, Derived Tables, and View References
8.2.3 Optimizing INFORMATION_SCHEMA Queries
8.2.4 Optimizing Data Change Statements
8.2.5 Optimizing Database Privileges
8.2.6 Other Optimization Tips
8.3 Optimization and Indexes
8.3.1 How MySQL Uses Indexes
8.3.2 Primary Key Optimization
8.3.3 Foreign Key Optimization
8.3.4 Column Indexes
8.3.5 Multiple-Column Indexes
8.3.6 Verifying Index Usage
8.3.7 InnoDB and MyISAM Index Statistics Collection
8.3.8 Comparison of B-Tree and Hash Indexes
8.3.9 Use of Index Extensions
8.3.10 Optimizer Use of Generated Column Indexes
8.3.11 Indexed Lookups from TIMESTAMP Columns
8.4 Optimizing Database Structure
8.4.1 Optimizing Data Size
8.4.2 Optimizing MySQL Data Types
8.4.3 Optimizing for Many Tables
8.4.4 Internal Temporary Table Use in MySQL
8.4.5 Limits on Number of Databases and Tables
8.4.6 Limits on Table Size
8.4.7 Limits on Table Column Count and Row Size
8.5 Optimizing for InnoDB Tables
8.5.1 Optimizing Storage Layout for InnoDB Tables
8.5.2 Optimizing InnoDB Transaction Management
8.5.3 Optimizing InnoDB Read-Only Transactions
8.5.4 Optimizing InnoDB Redo Logging
8.5.5 Bulk Data Loading for InnoDB Tables
8.5.6 Optimizing InnoDB Queries
8.5.7 Optimizing InnoDB DDL Operations
8.5.8 Optimizing InnoDB Disk I/O
8.5.9 Optimizing InnoDB Configuration Variables
8.5.10 Optimizing InnoDB for Systems with Many Tables
8.6 Optimizing for MyISAM Tables
8.6.1 Optimizing MyISAM Queries
8.6.2 Bulk Data Loading for MyISAM Tables
8.6.3 Optimizing REPAIR TABLE Statements
8.7 Optimizing for MEMORY Tables
8.8 Understanding the Query Execution Plan
8.8.1 Optimizing Queries with EXPLAIN
8.8.2 EXPLAIN Output Format
8.8.3 Extended EXPLAIN Output Format
8.8.4 Obtaining Execution Plan Information for a Named Connection
8.8.5 Estimating Query Performance
8.9 Controlling the Query Optimizer
8.9.1 Controlling Query Plan Evaluation
8.9.2 Switchable Optimizations
8.9.3 Optimizer Hints
8.9.4 Index Hints
8.9.5 The Optimizer Cost Model
8.10 Buffering and Caching
8.10.1 InnoDB Buffer Pool Optimization
8.10.2 The MyISAM Key Cache
8.10.3 The MySQL Query Cache
8.10.4 Caching of Prepared Statements and Stored Programs
8.11 Optimizing Locking Operations
8.11.1 Internal Locking Methods
8.11.2 Table Locking Issues
8.11.3 Concurrent Inserts
8.11.4 Metadata Locking
8.11.5 External Locking
8.12 Optimizing the MySQL Server
8.12.1 System Factors
8.12.2 Optimizing Disk I/O
8.12.3 Using Symbolic Links
8.12.4 Optimizing Memory Use
8.13 Measuring Performance (Benchmarking)
8.13.1 Measuring the Speed of Expressions and Functions
8.13.2 Using Your Own Benchmarks
8.13.3 Measuring Performance with performance_schema
8.14 Examining Server Thread (Process) Information
8.14.1 Accessing the Process List
8.14.2 Thread Command Values
8.14.3 General Thread States
8.14.4 Query Cache Thread States
8.14.5 Replication Source Thread States
8.14.6 Replication Replica I/O Thread States
8.14.7 Replication Replica SQL Thread States
8.14.8 Replication Replica Connection Thread States
8.14.9 NDB Cluster Thread States
8.14.10 Event Scheduler Thread States
9 Language Structure
9.1 Literal Values
9.1.1 String Literals
9.1.2 Numeric Literals
9.1.3 Date and Time Literals
9.1.4 Hexadecimal Literals
9.1.5 Bit-Value Literals
9.1.6 Boolean Literals
9.1.7 NULL Values
9.2 Schema Object Names
9.2.1 Identifier Length Limits
9.2.2 Identifier Qualifiers
9.2.3 Identifier Case Sensitivity
9.2.4 Mapping of Identifiers to File Names
9.2.5 Function Name Parsing and Resolution
9.3 Keywords and Reserved Words
9.4 User-Defined Variables
9.5 Expressions
9.6 Comment Syntax
10 Character Sets, Collations, Unicode
10.1 Character Sets and Collations in General
10.2 Character Sets and Collations in MySQL
10.2.1 Character Set Repertoire
10.2.2 UTF-8 for Metadata
10.3 Specifying Character Sets and Collations
10.3.1 Collation Naming Conventions
10.3.2 Server Character Set and Collation
10.3.3 Database Character Set and Collation
10.3.4 Table Character Set and Collation
10.3.5 Column Character Set and Collation
10.3.6 Character String Literal Character Set and Collation
10.3.7 The National Character Set
10.3.8 Character Set Introducers
10.3.9 Examples of Character Set and Collation Assignment
10.3.10 Compatibility with Other DBMSs
10.4 Connection Character Sets and Collations
10.5 Configuring Application Character Set and Collation
10.6 Error Message Character Set
10.7 Column Character Set Conversion
10.8 Collation Issues
10.8.1 Using COLLATE in SQL Statements
10.8.2 COLLATE Clause Precedence
10.8.3 Character Set and Collation Compatibility
10.8.4 Collation Coercibility in Expressions
10.8.5 The binary Collation Compared to _bin Collations
10.8.6 Examples of the Effect of Collation
10.8.7 Using Collation in INFORMATION_SCHEMA Searches
10.9 Unicode Support
10.9.1 The utf8mb4 Character Set (4-Byte UTF-8 Unicode Encoding)
10.9.2 The utf8mb3 Character Set (3-Byte UTF-8 Unicode Encoding)
10.9.3 The utf8 Character Set (Alias for utf8mb3)
10.9.4 The ucs2 Character Set (UCS-2 Unicode Encoding)
10.9.5 The utf16 Character Set (UTF-16 Unicode Encoding)
10.9.6 The utf16le Character Set (UTF-16LE Unicode Encoding)
10.9.7 The utf32 Character Set (UTF-32 Unicode Encoding)
10.9.8 Converting Between 3-Byte and 4-Byte Unicode Character Sets
10.10 Supported Character Sets and Collations
10.10.1 Unicode Character Sets
10.10.2 West European Character Sets
10.10.3 Central European Character Sets
10.10.4 South European and Middle East Character Sets
10.10.5 Baltic Character Sets
10.10.6 Cyrillic Character Sets
10.10.7 Asian Character Sets
10.10.8 The Binary Character Set
10.11 Restrictions on Character Sets
10.12 Setting the Error Message Language
10.13 Adding a Character Set
10.13.1 Character Definition Arrays
10.13.2 String Collating Support for Complex Character Sets
10.13.3 Multi-Byte Character Support for Complex Character Sets
10.14 Adding a Collation to a Character Set
10.14.1 Collation Implementation Types
10.14.2 Choosing a Collation ID
10.14.3 Adding a Simple Collation to an 8-Bit Character Set
10.14.4 Adding a UCA Collation to a Unicode Character Set
10.15 Character Set Configuration
10.16 MySQL Server Locale Support
11 Data Types
11.1 Numeric Data Types
11.1.1 Numeric Data Type Syntax
11.1.3 Fixed-Point Types (Exact Value) - DECIMAL, NUMERIC
11.1.4 Floating-Point Types (Approximate Value) - FLOAT, DOUBLE
11.1.5 Bit-Value Type - BIT
11.1.6 Numeric Type Attributes
11.1.7 Out-of-Range and Overflow Handling
11.2 Date and Time Data Types
11.2.1 Date and Time Data Type Syntax
11.2.2 The DATE, DATETIME, and TIMESTAMP Types
11.2.3 The TIME Type
11.2.4 The YEAR Type
11.2.5 2-Digit YEAR(2) Limitations and Migrating to 4-Digit YEAR
11.2.6 Automatic Initialization and Updating for TIMESTAMP and DATETIME
11.2.7 Fractional Seconds in Time Values
11.2.8 Conversion Between Date and Time Types
11.2.9 2-Digit Years in Dates
11.3 String Data Types
11.3.1 String Data Type Syntax
11.3.2 The CHAR and VARCHAR Types
11.3.3 The BINARY and VARBINARY Types
11.3.4 The BLOB and TEXT Types
11.3.5 The ENUM Type
11.3.6 The SET Type
11.4 Spatial Data Types
11.4.1 Spatial Data Types
11.4.2 The OpenGIS Geometry Model
11.4.3 Supported Spatial Data Formats
11.4.4 Geometry Well-Formedness and Validity
11.4.5 Creating Spatial Columns
11.4.6 Populating Spatial Columns
11.4.7 Fetching Spatial Data
11.4.8 Optimizing Spatial Analysis
11.4.9 Creating Spatial Indexes
11.4.10 Using Spatial Indexes
11.5 The JSON Data Type
11.6 Data Type Default Values
11.7 Data Type Storage Requirements
11.8 Choosing the Right Type for a Column
11.9 Using Data Types from Other Database Engines
12 Functions and Operators
12.1 Function and Operator Reference
12.2 Type Conversion in Expression Evaluation
12.3 Operators
12.3.1 Operator Precedence
12.3.2 Comparison Functions and Operators
12.3.3 Logical Operators
12.3.4 Assignment Operators
12.4 Control Flow Functions
12.5 Numeric Functions and Operators
12.5.1 Arithmetic Operators
12.5.2 Mathematical Functions
12.6 Date and Time Functions
12.7 String Functions and Operators
12.7.1 String Comparison Functions and Operators
12.7.2 Regular Expressions
12.7.3 Character Set and Collation of Function Results
12.8 What Calendar Is Used By MySQL?
12.9 Full-Text Search Functions
12.9.1 Natural Language Full-Text Searches
12.9.2 Boolean Full-Text Searches
12.9.3 Full-Text Searches with Query Expansion
12.9.4 Full-Text Stopwords
12.9.5 Full-Text Restrictions
12.9.6 Fine-Tuning MySQL Full-Text Search
12.9.7 Adding a Collation for Full-Text Indexing
12.9.8 ngram Full-Text Parser
12.9.9 MeCab Full-Text Parser Plugin
12.10 Cast Functions and Operators
12.11 XML Functions
12.12 Bit Functions and Operators
12.13 Encryption and Compression Functions
12.14 Locking Functions
12.15 Information Functions
12.16 Spatial Analysis Functions
12.16.1 Spatial Function Reference
12.16.2 Argument Handling by Spatial Functions
12.16.3 Functions That Create Geometry Values from WKT Values
12.16.4 Functions That Create Geometry Values from WKB Values
12.16.5 MySQL-Specific Functions That Create Geometry Values
12.16.6 Geometry Format Conversion Functions
12.16.7 Geometry Property Functions
12.16.8 Spatial Operator Functions
12.16.9 Functions That Test Spatial Relations Between Geometry Objects
12.16.10 Spatial Geohash Functions
12.16.11 Spatial GeoJSON Functions
12.16.12 Spatial Convenience Functions
12.17 JSON Functions
12.17.1 JSON Function Reference
12.17.2 Functions That Create JSON Values
12.17.3 Functions That Search JSON Values
12.17.4 Functions That Modify JSON Values
12.17.5 Functions That Return JSON Value Attributes
12.17.6 JSON Utility Functions
12.18 Functions Used with Global Transaction Identifiers (GTIDs)
12.19 MySQL Enterprise Encryption Functions
12.19.1 MySQL Enterprise Encryption Installation
12.19.2 MySQL Enterprise Encryption Usage and Examples
12.19.3 MySQL Enterprise Encryption Function Reference
12.19.4 MySQL Enterprise Encryption Function Descriptions
12.20 Aggregate Functions
12.20.1 Aggregate Function Descriptions
12.20.2 GROUP BY Modifiers
12.20.3 MySQL Handling of GROUP BY
12.20.4 Detection of Functional Dependence
12.21 Miscellaneous Functions
12.22 Precision Math
12.22.1 Types of Numeric Values
12.22.2 DECIMAL Data Type Characteristics
12.22.3 Expression Handling
12.22.4 Rounding Behavior
12.22.5 Precision Math Examples
13 SQL Statements
13.1 Data Definition Statements
13.1.1 ALTER DATABASE Statement
13.1.2 ALTER EVENT Statement
13.1.3 ALTER FUNCTION Statement
13.1.4 ALTER INSTANCE Statement
13.1.5 ALTER LOGFILE GROUP Statement
13.1.6 ALTER PROCEDURE Statement
13.1.7 ALTER SERVER Statement
13.1.8 ALTER TABLE Statement
13.1.9 ALTER TABLESPACE Statement
13.1.10 ALTER VIEW Statement
13.1.11 CREATE DATABASE Statement
13.1.12 CREATE EVENT Statement
13.1.13 CREATE FUNCTION Statement
13.1.14 CREATE INDEX Statement
13.1.15 CREATE LOGFILE GROUP Statement
13.1.17 CREATE SERVER Statement
13.1.18 CREATE TABLE Statement
13.1.19 CREATE TABLESPACE Statement
13.1.20 CREATE TRIGGER Statement
13.1.21 CREATE VIEW Statement
13.1.22 DROP DATABASE Statement
13.1.23 DROP EVENT Statement
13.1.24 DROP FUNCTION Statement
13.1.25 DROP INDEX Statement
13.1.26 DROP LOGFILE GROUP Statement
13.1.28 DROP SERVER Statement
13.1.29 DROP TABLE Statement
13.1.30 DROP TABLESPACE Statement
13.1.31 DROP TRIGGER Statement
13.1.32 DROP VIEW Statement
13.1.33 RENAME TABLE Statement
13.1.34 TRUNCATE TABLE Statement
13.2 Data Manipulation Statements
13.2.1 CALL Statement
13.2.2 DELETE Statement
13.2.3 DO Statement
13.2.4 HANDLER Statement
13.2.5 INSERT Statement
13.2.6 LOAD DATA Statement
13.2.7 LOAD XML Statement
13.2.8 REPLACE Statement
13.2.9 SELECT Statement
13.2.10 Subqueries
13.2.11 UPDATE Statement
13.3 Transactional and Locking Statements
13.3.2 Statements That Cannot Be Rolled Back
13.3.3 Statements That Cause an Implicit Commit
13.3.5 LOCK TABLES and UNLOCK TABLES Statements
13.3.6 SET TRANSACTION Statement
13.3.7 XA Transactions
13.4 Replication Statements
13.4.1 SQL Statements for Controlling Replication Source Servers
13.4.2 SQL Statements for Controlling Replica Servers
13.4.3 SQL Statements for Controlling Group Replication
13.5 Prepared Statements
13.5.1 PREPARE Statement
13.5.2 EXECUTE Statement
13.6 Compound Statements
13.6.1 BEGIN ... END Compound Statement
13.6.2 Statement Labels
13.6.3 DECLARE Statement
13.6.4 Variables in Stored Programs
13.6.5 Flow Control Statements
13.6.6 Cursors
13.6.7 Condition Handling
13.7 Database Administration Statements
13.7.1 Account Management Statements
13.7.2 Table Maintenance Statements
13.7.3 Plugin and User-Defined Function Statements
13.7.4 SET Statements
13.7.5 SHOW Statements
13.7.6 Other Administrative Statements
13.8 Utility Statements
13.8.1 DESCRIBE Statement
13.8.2 EXPLAIN Statement
13.8.3 HELP Statement
13.8.4 USE Statement
14 The InnoDB Storage Engine
14.1 Introduction to InnoDB
14.1.1 Benefits of Using InnoDB Tables
14.1.2 Best Practices for InnoDB Tables
14.1.3 Verifying that InnoDB is the Default Storage Engine
14.1.4 Testing and Benchmarking with InnoDB
14.1.5 Turning Off InnoDB
14.2 InnoDB and the ACID Model
14.3 InnoDB Multi-Versioning
14.4 InnoDB Architecture
14.5 InnoDB In-Memory Structures
14.5.1 Buffer Pool
14.5.2 Change Buffer
14.5.3 Adaptive Hash Index
14.5.4 Log Buffer
14.6 InnoDB On-Disk Structures
14.6.1 Tables
14.6.2 Indexes
14.6.3 Tablespaces
14.6.4 InnoDB Data Dictionary
14.6.5 Doublewrite Buffer
14.6.6 Redo Log
14.6.7 Undo Logs
14.7 InnoDB Locking and Transaction Model
14.7.1 InnoDB Locking
14.7.2 InnoDB Transaction Model
14.7.3 Locks Set by Different SQL Statements in InnoDB
14.7.4 Phantom Rows
14.7.5 Deadlocks in InnoDB
14.8 InnoDB Configuration
14.8.1 InnoDB Startup Configuration
14.8.2 Configuring InnoDB for Read-Only Operation
14.8.3 InnoDB Buffer Pool Configuration
14.8.4 Configuring the Memory Allocator for InnoDB
14.8.5 Configuring Thread Concurrency for InnoDB
14.8.6 Configuring the Number of Background InnoDB I/O Threads
14.8.7 Using Asynchronous I/O on Linux
14.8.8 Configuring InnoDB I/O Capacity
14.8.9 Configuring Spin Lock Polling
14.8.10 Purge Configuration
14.8.11 Configuring Optimizer Statistics for InnoDB
14.8.12 Configuring the Merge Threshold for Index Pages
14.9 InnoDB Table and Page Compression
14.9.1 InnoDB Table Compression
14.9.2 InnoDB Page Compression
14.10 InnoDB File-Format Management
14.10.1 Enabling File Formats
14.10.2 Verifying File Format Compatibility
14.10.3 Identifying the File Format in Use
14.10.4 Modifying the File Format
14.11 InnoDB Row Formats
14.12 InnoDB Disk I/O and File Space Management
14.12.1 InnoDB Disk I/O
14.12.2 File Space Management
14.12.3 InnoDB Checkpoints
14.12.4 Defragmenting a Table
14.12.5 Reclaiming Disk Space with TRUNCATE TABLE
14.13 InnoDB and Online DDL
14.13.1 Online DDL Operations
14.13.2 Online DDL Performance and Concurrency
14.13.3 Online DDL Space Requirements
14.13.4 Simplifying DDL Statements with Online DDL
14.13.5 Online DDL Failure Conditions
14.13.6 Online DDL Limitations
14.14 InnoDB Data-at-Rest Encryption
14.15 InnoDB Startup Options and System Variables
14.16.1 InnoDB INFORMATION_SCHEMA Tables about Compression
14.16.2 InnoDB INFORMATION_SCHEMA Transaction and Locking Information
14.16.3 InnoDB INFORMATION_SCHEMA System Tables
14.16.5 InnoDB INFORMATION_SCHEMA Buffer Pool Tables
14.16.6 InnoDB INFORMATION_SCHEMA Metrics Table
14.16.7 InnoDB INFORMATION_SCHEMA Temporary Table Info Table
14.16.8 Retrieving InnoDB Tablespace Metadata from INFORMATION_SCHEMA.FILES
14.17 InnoDB Integration with MySQL Performance Schema
14.17.1 Monitoring ALTER TABLE Progress for InnoDB Tables Using Performance Schema
14.17.2 Monitoring InnoDB Mutex Waits Using Performance Schema
14.18 InnoDB Monitors
14.18.1 InnoDB Monitor Types
14.18.2 Enabling InnoDB Monitors
14.18.3 InnoDB Standard Monitor and Lock Monitor Output
14.19 InnoDB Backup and Recovery
14.19.1 InnoDB Backup
14.19.2 InnoDB Recovery
14.20 InnoDB and MySQL Replication
14.21 InnoDB memcached Plugin
14.21.1 Benefits of the InnoDB memcached Plugin
14.21.2 InnoDB memcached Architecture
14.21.3 Setting Up the InnoDB memcached Plugin
14.21.4 Security Considerations for the InnoDB memcached Plugin
14.21.5 Writing Applications for the InnoDB memcached Plugin
14.21.6 The InnoDB memcached Plugin and Replication
14.21.7 InnoDB memcached Plugin Internals
14.21.8 Troubleshooting the InnoDB memcached Plugin
14.22 InnoDB Troubleshooting
14.22.1 Troubleshooting InnoDB I/O Problems
14.22.2 Forcing InnoDB Recovery
14.22.3 Troubleshooting InnoDB Data Dictionary Operations
14.22.4 InnoDB Error Handling
14.23 InnoDB Limits
14.24 InnoDB Restrictions and Limitations
15 Alternative Storage Engines
15.1 Setting the Storage Engine
15.2 The MyISAM Storage Engine
15.2.1 MyISAM Startup Options
15.2.2 Space Needed for Keys
15.2.3 MyISAM Table Storage Formats
15.2.4 MyISAM Table Problems
15.3 The MEMORY Storage Engine
15.4 The CSV Storage Engine
15.4.1 Repairing and Checking CSV Tables
15.4.2 CSV Limitations
15.5 The ARCHIVE Storage Engine
15.6 The BLACKHOLE Storage Engine
15.7 The MERGE Storage Engine
15.7.1 MERGE Table Advantages and Disadvantages
15.7.2 MERGE Table Problems
15.8 The FEDERATED Storage Engine
15.8.1 FEDERATED Storage Engine Overview
15.8.2 How to Create FEDERATED Tables
15.8.3 FEDERATED Storage Engine Notes and Tips
15.8.4 FEDERATED Storage Engine Resources
15.9 The EXAMPLE Storage Engine
15.10 Other Storage Engines
15.11 Overview of MySQL Storage Engine Architecture
15.11.1 Pluggable Storage Engine Architecture
15.11.2 The Common Database Server Layer
16 Replication
16.1 Configuring Replication
16.1.1 Binary Log File Position Based Replication Configuration Overview
16.1.2 Setting Up Binary Log File Position Based Replication
16.1.3 Replication with Global Transaction Identifiers
16.1.4 Changing Replication Modes on Online Servers
16.1.5 MySQL Multi-Source Replication
16.1.6 Replication and Binary Logging Options and Variables
16.1.7 Common Replication Administration Tasks
16.2 Replication Implementation
16.2.1 Replication Formats
16.2.2 Replication Implementation Details
16.2.3 Replication Channels
16.2.4 Relay Log and Replication Applier Metadata Repositories
16.2.5 How Servers Evaluate Replication Filtering Rules
16.3 Replication Solutions
16.3.1 Using Replication for Backups
16.3.2 Handling an Unexpected Halt of a Replica
16.3.3 Using Replication with Different Source and Replica Storage Engines
16.3.4 Using Replication for Scale-Out
16.3.5 Replicating Different Databases to Different Replicas
16.3.6 Improving Replication Performance
16.3.7 Switching Sources During Failover
16.3.8 Setting Up Replication to Use Encrypted Connections
16.3.9 Semisynchronous Replication
16.3.10 Delayed Replication
16.4 Replication Notes and Tips
16.4.1 Replication Features and Issues
16.4.2 Replication Compatibility Between MySQL Versions
16.4.3 Upgrading a Replication Setup
16.4.4 Troubleshooting Replication
16.4.5 How to Report Replication Bugs or Problems
17 Group Replication
17.1 Group Replication Background
17.1.1 Replication Technologies
17.1.2 Group Replication Use Cases
17.1.3 Group Replication Details
17.2 Getting Started
17.2.1 Deploying Group Replication in Single-Primary Mode
17.2.2 Deploying Group Replication Locally
17.3 Monitoring Group Replication
17.3.1 Group Replication Server States
17.3.2 The replication_group_members Table
17.3.3 The replication_group_member_stats Table
17.4 Group Replication Operations
17.4.1 Deploying in Multi-Primary or Single-Primary Mode
17.4.2 Tuning Recovery
17.4.3 Network Partitioning
17.4.4 Using MySQL Enterprise Backup with Group Replication
17.5 Group Replication Security
17.5.1 Group Replication IP Address Allowlisting
17.5.2 Group Replication Secure Socket Layer (SSL) Support
17.5.3 Group Replication and Virtual Private Networks (VPNs)
17.6 Group Replication System Variables
17.7 Requirements and Limitations
17.7.1 Group Replication Requirements
17.7.2 Group Replication Limitations
17.8 Frequently Asked Questions
17.9 Group Replication Technical Details
17.9.1 Group Replication Plugin Architecture
17.9.2 The Group
17.9.3 Data Manipulation Statements
17.9.4 Data Definition Statements
17.9.5 Distributed Recovery
17.9.6 Observability
17.9.7 Group Replication Performance
18 MySQL Shell
19 Using MySQL as a Document Store
19.1 Key Concepts
19.2 Setting Up MySQL as a Document Store
19.2.1 Installing MySQL Shell
19.2.2 Starting MySQL Shell
19.3 Quick-Start Guide: MySQL for Visual Studio
19.4 X Plugin
19.4.1 Using Encrypted Connections with X Plugin
19.4.2 X Plugin Options and Variables
19.4.3 Monitoring X Plugin
20 InnoDB Cluster
20.1 Introducing InnoDB Cluster
20.2 Creating an InnoDB Cluster
20.2.1 Deployment Scenarios
20.2.2 InnoDB Cluster Requirements
20.2.3 Methods of Installing
20.2.4 Sandbox Deployment of InnoDB Cluster
20.2.5 Production Deployment of InnoDB Cluster
20.2.6 Adopting a Group Replication Deployment
20.3 Using MySQL Router with InnoDB Cluster
20.4 Working with InnoDB Cluster
20.5 Known Limitations
21 MySQL NDB Cluster 7.5 and NDB Cluster 7.6
21.1 NDB Cluster Overview
21.1.1 NDB Cluster Core Concepts
21.1.2 NDB Cluster Nodes, Node Groups, Replicas, and Partitions
21.1.3 NDB Cluster Hardware, Software, and Networking Requirements
21.1.4 What is New in NDB Cluster
21.1.5 NDB: Added, Deprecated, and Removed Options, Variables, and Parameters
21.1.6 MySQL Server Using InnoDB Compared with NDB Cluster
21.1.7 Known Limitations of NDB Cluster
21.2 NDB Cluster Installation
21.2.1 The NDB Cluster Auto-Installer (NDB 7.5)
21.2.2 The NDB Cluster Auto-Installer (NDB 7.6)
21.2.3 Installation of NDB Cluster on Linux
21.2.4 Installing NDB Cluster on Windows
21.2.5 Initial Configuration of NDB Cluster
21.2.6 Initial Startup of NDB Cluster
21.2.7 NDB Cluster Example with Tables and Data
21.2.8 Safe Shutdown and Restart of NDB Cluster
21.2.9 Upgrading and Downgrading NDB Cluster
21.3 Configuration of NDB Cluster
21.3.1 Quick Test Setup of NDB Cluster
21.3.2 Overview of NDB Cluster Configuration Parameters, Options, and Variables
21.3.3 NDB Cluster Configuration Files
21.3.4 Using High-Speed Interconnects with NDB Cluster
21.4 NDB Cluster Programs
21.4.1 ndbd — The NDB Cluster Data Node Daemon
21.4.2 ndbinfo_select_all — Select From ndbinfo Tables
21.4.3 ndbmtd — The NDB Cluster Data Node Daemon (Multi-Threaded)
21.4.4 ndb_mgmd — The NDB Cluster Management Server Daemon
21.4.5 ndb_mgm — The NDB Cluster Management Client
21.4.6 ndb_blob_tool — Check and Repair BLOB and TEXT columns of NDB Cluster Tables
21.4.7 ndb_config — Extract NDB Cluster Configuration Information
21.4.8 ndb_cpcd — Automate Testing for NDB Development
21.4.9 ndb_delete_all — Delete All Rows from an NDB Table
21.4.10 ndb_desc — Describe NDB Tables
21.4.11 ndb_drop_index — Drop Index from an NDB Table
21.4.12 ndb_drop_table — Drop an NDB Table
21.4.13 ndb_error_reporter — NDB Error-Reporting Utility
21.4.14 ndb_import — Import CSV Data Into NDB
21.4.15 ndb_index_stat — NDB Index Statistics Utility
21.4.16 ndb_move_data — NDB Data Copy Utility
21.4.17 ndb_perror — Obtain NDB Error Message Information
21.4.18 ndb_print_backup_file — Print NDB Backup File Contents
21.4.19 ndb_print_file — Print NDB Disk Data File Contents
21.4.20 ndb_print_frag_file — Print NDB Fragment List File Contents
21.4.21 ndb_print_schema_file — Print NDB Schema File Contents
21.4.22 ndb_print_sys_file — Print NDB System File Contents
21.4.23 ndb_redo_log_reader — Check and Print Content of Cluster Redo Log
21.4.24 ndb_restore — Restore an NDB Cluster Backup
21.4.25 ndb_select_all — Print Rows from an NDB Table
21.4.26 ndb_select_count — Print Row Counts for NDB Tables
21.4.27 — Start browser-based Auto-Installer for NDB Cluster
21.4.28 ndb_show_tables — Display List of NDB Tables
21.4.29 — NDBCLUSTER Size Requirement Estimator
21.4.30 ndb_top — View CPU usage information for NDB threads
21.4.31 ndb_waiter — Wait for NDB Cluster to Reach a Given Status
21.4.32 Options Common to NDB Cluster Programs — Options Common to NDB Cluster Programs
21.5 Management of NDB Cluster
21.5.1 Commands in the NDB Cluster Management Client
21.5.2 NDB Cluster Log Messages
21.5.3 Event Reports Generated in NDB Cluster
21.5.4 Summary of NDB Cluster Start Phases
21.5.5 Performing a Rolling Restart of an NDB Cluster
21.5.6 NDB Cluster Single User Mode
21.5.7 Adding NDB Cluster Data Nodes Online
21.5.8 Online Backup of NDB Cluster
21.5.9 MySQL Server Usage for NDB Cluster
21.5.10 NDB Cluster Disk Data Tables
21.5.11 Online Operations with ALTER TABLE in NDB Cluster
21.5.12 Distributed Privileges Using Shared Grant Tables
21.5.13 NDB API Statistics Counters and Variables
21.5.14 ndbinfo: The NDB Cluster Information Database
21.5.15 INFORMATION_SCHEMA Tables for NDB Cluster
21.5.16 Quick Reference: NDB Cluster SQL Statements
21.5.17 NDB Cluster Security Issues
21.6 NDB Cluster Replication
21.6.1 NDB Cluster Replication: Abbreviations and Symbols
21.6.2 General Requirements for NDB Cluster Replication
21.6.3 Known Issues in NDB Cluster Replication
21.6.4 NDB Cluster Replication Schema and Tables
21.6.5 Preparing the NDB Cluster for Replication
21.6.6 Starting NDB Cluster Replication (Single Replicat