The HandlerSocket plugin has the following options.

See also the Full list of MariaDB options, system and status variables.

Add the options to the [mysqld] section of your my.cnf file.

handlersocket_accept_balance

• Description: When set to a value other than zero ('0'), handlersocket will try to balance accepted connections among threads. Default is 0 but if you use persistent connections (for example if you use client-side connection pooling) then a non-zero value is recommended.
• Commandline: --handlersocket-accept-balance="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 0 to 10000
• Default Value: 0
• Introduced: MariaDB 5.3

handlersocket_address

• Description: Specify the IP address to bind to.
• Commandline: --handlersocket-address="value"
• Scope: Global
• Dynamic: No
• Type: IP Address
• Default Value: Empty, previously 0.0.0.0
• Introduced: MariaDB 5.3

handlersocket_backlog

• Description: Specify the listen backlog length.
• Commandline: --handlersocket-backlog="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 5 to 1000000
• Default Value: 32768
• Introduced: MariaDB 5.3

handlersocket_epoll

• Description: Specify whether to use epoll for I/O multiplexing.
• Commandline: --handlersocket-epoll="value"
• Scope: Global
• Dynamic: No
• Type: number
• Valid values:
  • Min: 0
  • Max: 1
• Default Value: 1
• Introduced: MariaDB 5.3

handlersocket_plain_secret

• Description: When set, enables plain-text authentication for the listener for read requests, with the value of the option specifying the secret authentication key.
• Commandline: --handlersocket-plain-secret="value"
• Dynamic: No
• Type: string
• Default Value: Empty

handlersocket_plain_secret_wr

• Description: When set, enables plain-text authentication for the listener for write requests, with the value of the option specifying the secret authentication key.
• Commandline: --handlersocket-plain-secret-wr="value"
• Dynamic: No
• Type: string
• Default Value: Empty

handlersocket_port

• Description: Specify the port to bind to for reads. An empty value disables the listener.
• Commandline: --handlersocket-port="value"
• Scope: Global
• Dynamic: No
• Type: number
• Default Value: Empty, previously 9998
• Introduced: MariaDB 5.3

handlersocket_port_wr

• Description: Specify the port to bind to for writes. An empty value disables the listener.
• Commandline: --handlersocket-port-wr="value"
• Scope: Global
• Dynamic: No
• Type: number
• Default Value: Empty, previously 9999
• Introduced: MariaDB 5.3

handlersocket_rcvbuf

• Description: Specify the maximum socket receive buffer (in bytes). If '0' then the system default is used.
• Commandline: --handlersocket-rcvbuf="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 0 to 1677216
• Default Value: 0
• Introduced: MariaDB 5.3

handlersocket_readsize

• Description: Specify the minimum length of the request buffer. Larger values consume available memory but can make handlersocket faster for large requests.
• Commandline: --handlersocket-readsize="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 0 to 1677216
• Default Value: 0 (possibly 4096)
• Introduced: MariaDB 5.3

handlersocket_sndbuf

• Description: Specify the maximum socket send buffer (in bytes). If '0' then the system default is used.
• Commandline: --handlersocket-sndbuf="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 0 to 1677216
• Default Value: 0
• Introduced: MariaDB 5.3

handlersocket_threads

• Description: Specify the number of worker threads for reads. Recommended value = ((# CPU cores) * 2).
• Commandline: --handlersocket-threads="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 1 to 3000
• Default Value: 16
• Introduced: MariaDB 5.3

handlersocket_threads_wr

• Description: Specify the number of worker threads for writes. Recommended value = 1.
• Commandline: --handlersocket-threads-wr="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 1 to 3000
• Default Value: 1
• Introduced: MariaDB 5.3

handlersocket_timeout

• Description: Specify the socket timeout in seconds.
• Commandline: --handlersocket-timeout="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 30 to 3600
• Default Value: 300
• Introduced: MariaDB 5.3

handlersocket_verbose

• Description: Specify the logging verbosity.
• Commandline: --handlersocket-verbose="value"
• Scope: Global
• Dynamic: No
• Type: number
• Valid values:
  • Min: 0
  • Max: 10000
• Default Value: 10
• Introduced: MariaDB 5.3

handlersocket_wrlock_timeout

• Description: The write lock timeout in seconds. When acting on write requests, handlersocket locks an advisory lock named 'handlersocket_wr' and this option sets the timeout for it.
• Commandline: --handlersocket-wrlock-timeout="value"
• Scope: Global
• Dynamic: No
• Type: number
• Range: 0 to 3600
• Introduced: MariaDB 5.3