# Go-MySQL-Driver
A MySQL-Driver for Go's [database/sql](https://golang.org/pkg/database/sql/) package
![Go-MySQL-Driver logo](https://raw.github.com/wiki/go-sql-driver/mysql/gomysql_m.png "Golang Gopher holding the MySQL Dolphin")
---------------------------------------
* [Features](#features)
* [Requirements](#requirements)
* [Installation](#installation)
* [Usage](#usage)
* [DSN (Data Source Name)](#dsn-data-source-name)
* [Password](#password)
* [Protocol](#protocol)
* [Address](#address)
* [Parameters](#parameters)
* [Examples](#examples)
* [Connection pool and timeouts](#connection-pool-and-timeouts)
* [context.Context Support](#contextcontext-support)
* [ColumnType Support](#columntype-support)
* [LOAD DATA LOCAL INFILE support](#load-data-local-infile-support)
* [time.Time support](#timetime-support)
* [Unicode support](#unicode-support)
* [Testing / Development](#testing--development)
* [License](#license)
---------------------------------------
## Features
* Lightweight and [fast](https://github.com/go-sql-driver/sql-benchmark "golang MySQL-Driver performance")
* Native Go implementation. No C-bindings, just pure Go
* Connections over TCP/IPv4, TCP/IPv6, Unix domain sockets or [custom protocols](https://godoc.org/github.com/go-sql-driver/mysql#DialFunc)
* Automatic handling of broken connections
* Automatic Connection Pooling *(by database/sql package)*
* Supports queries larger than 16MB
* Full [`sql.RawBytes`](https://golang.org/pkg/database/sql/#RawBytes) support.
* Intelligent `LONG DATA` handling in prepared statements
* Secure `LOAD DATA LOCAL INFILE` support with file allowlisting and `io.Reader` support
* Optional `time.Time` parsing
* Optional placeholder interpolation
## Requirements
* Go 1.10 or higher. We aim to support the 3 latest versions of Go.
* MySQL (4.1+), MariaDB, Percona Server, Google CloudSQL or Sphinx (2.2.3+)
---------------------------------------
## Installation
Simple install the package to your [$GOPATH](https://github.com/golang/go/wiki/GOPATH "GOPATH") with the [go tool](https://golang.org/cmd/go/ "go command") from shell:
```bash
$ go get -u github.com/go-sql-driver/mysql
```
Make sure [Git is installed](https://git-scm.com/downloads) on your machine and in your system's `PATH`.
## Usage
_Go MySQL Driver_ is an implementation of Go's `database/sql/driver` interface. You only need to import the driver and can use the full [`database/sql`](https://golang.org/pkg/database/sql/) API then.
Use `mysql` as `driverName` and a valid [DSN](#dsn-data-source-name) as `dataSourceName`:
```go
import (
"database/sql"
"time"
_ "github.com/go-sql-driver/mysql"
)
// ...
db, err := sql.Open("mysql", "user:password@/dbname")
if err != nil {
panic(err)
}
// See "Important settings" section.
db.SetConnMaxLifetime(time.Minute * 3)
db.SetMaxOpenConns(10)
db.SetMaxIdleConns(10)
```
[Examples are available in our Wiki](https://github.com/go-sql-driver/mysql/wiki/Examples "Go-MySQL-Driver Examples").
### Important settings
`db.SetConnMaxLifetime()` is required to ensure connections are closed by the driver safely before connection is closed by MySQL server, OS, or other middlewares. Since some middlewares close idle connections by 5 minutes, we recommend timeout shorter than 5 minutes. This setting helps load balancing and changing system variables too.
`db.SetMaxOpenConns()` is highly recommended to limit the number of connection used by the application. There is no recommended limit number because it depends on application and MySQL server.
`db.SetMaxIdleConns()` is recommended to be set same to (or greater than) `db.SetMaxOpenConns()`. When it is smaller than `SetMaxOpenConns()`, connections can be opened and closed very frequently than you expect. Idle connections can be closed by the `db.SetConnMaxLifetime()`. If you want to close idle connections more rapidly, you can use `db.SetConnMaxIdleTime()` since Go 1.15.
### DSN (Data Source Name)
The Data Source Name has a common format, like e.g. [PEAR DB](http://pear.php.net/manual/en/package.database.db.intro-dsn.php) uses it, but without type-prefix (optional parts marked by squared brackets):
```
[username[:password]@][protocol[(address)]]/dbname[?param1=value1&...¶mN=valueN]
```
A DSN in its fullest form:
```
username:password@protocol(address)/dbname?param=value
```
Except for the databasename, all values are optional. So the minimal DSN is:
```
/dbname
```
If you do not want to preselect a database, leave `dbname` empty:
```
/
```
This has the same effect as an empty DSN string:
```
```
Alternatively, [Config.FormatDSN](https://godoc.org/github.com/go-sql-driver/mysql#Config.FormatDSN) can be used to create a DSN string by filling a struct.
#### Password
Passwords can consist of any character. Escaping is **not** necessary.
#### Protocol
See [net.Dial](https://golang.org/pkg/net/#Dial) for more information which networks are available.
In general you should use an Unix domain socket if available and TCP otherwise for best performance.
#### Address
For TCP and UDP networks, addresses have the form `host[:port]`.
If `port` is omitted, the default port will be used.
If `host` is a literal IPv6 address, it must be enclosed in square brackets.
The functions [net.JoinHostPort](https://golang.org/pkg/net/#JoinHostPort) and [net.SplitHostPort](https://golang.org/pkg/net/#SplitHostPort) manipulate addresses in this form.
For Unix domain sockets the address is the absolute path to the MySQL-Server-socket, e.g. `/var/run/mysqld/mysqld.sock` or `/tmp/mysql.sock`.
#### Parameters
*Parameters are case-sensitive!*
Notice that any of `true`, `TRUE`, `True` or `1` is accepted to stand for a true boolean value. Not surprisingly, false can be specified as any of: `false`, `FALSE`, `False` or `0`.
##### `allowAllFiles`
```
Type: bool
Valid Values: true, false
Default: false
```
`allowAllFiles=true` disables the file allowlist for `LOAD DATA LOCAL INFILE` and allows *all* files.
[*Might be insecure!*](http://dev.mysql.com/doc/refman/5.7/en/load-data-local.html)
##### `allowCleartextPasswords`
```
Type: bool
Valid Values: true, false
Default: false
```
`allowCleartextPasswords=true` allows using the [cleartext client side plugin](https://dev.mysql.com/doc/en/cleartext-pluggable-authentication.html) if required by an account, such as one defined with the [PAM authentication plugin](http://dev.mysql.com/doc/en/pam-authentication-plugin.html). Sending passwords in clear text may be a security problem in some configurations. To avoid problems if there is any possibility that the password would be intercepted, clients should connect to MySQL Server using a method that protects the password. Possibilities include [TLS / SSL](#tls), IPsec, or a private network.
##### `allowNativePasswords`
```
Type: bool
Valid Values: true, false
Default: true
```
`allowNativePasswords=false` disallows the usage of MySQL native password method.
##### `allowOldPasswords`
```
Type: bool
Valid Values: true, false
Default: false
```
`allowOldPasswords=true` allows the usage of the insecure old password method. This should be avoided, but is necessary in some cases. See also [the old_passwords wiki page](https://github.com/go-sql-driver/mysql/wiki/old_passwords).
##### `charset`
```
Type: string
Valid Values: <name>
Default: none
```
Sets the charset used for client-server interaction (`"SET NAMES <value>"`). If multiple charsets are set (separated by a comma), the following charset is used if setting the charset failes. This enables for example support for `utf8mb4` ([introduced in MySQL 5.5.3](http://dev.mysql.com/doc/refman/5.5/en/charset-unicode-utf8mb4.html)) with fallback to `utf8` for older servers (`charset=utf8mb4,utf8`).
Usage of the `charset` parameter is discouraged because