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{ “title”: “SET VARIABLE”, “language”: “en”, “description”: “This statement is mainly used to modify Doris system variables. These system variables can be modified at the global and session level,” }

Description

This statement is mainly used to modify Doris system variables. These system variables can be modified at the global and session level, and some can also be modified dynamically. You can also view these system variables with SHOW VARIABLE.

Syntax

SET variable_assignment [, variable_assignment] [ ... ]

Where:

variable_assignment
  : <user_var_name> = <expr>
  | [ <effective_scope> ] <system_var_name> = <expr>

Required Parameters

1. <user_var_name>

Specifies the variable of user level, for example : @@your_variable_name, variable name starts with @@

2. <system_var_name>

Specifies the variable of system level, for example : exec_mem_limit and so on

Optional Parameters

1. <effective_scope>

Effective scope is one of GLOBAL or SESSION or LOCAL. If there is no effective scope, default value is SESSION. LOCAL is an alias of SESSION.

Access Control Requirements

Users executing this SQL command must have at least the following privileges:

Privilege	Object	Notes
ADMIN_PRIV	Session	set global variables need admin privilege

Usage Notes

• Only ADMIN users can set variables to take effect globally
• The globally effective variable affects the current session and new sessions thereafter, but does not affect other sessions that currently exist.

Example

• Set the time zone to East Eighth District

  SET time_zone = "Asia/Shanghai";
  

• Set the global execution memory size

  SET GLOBAL exec_mem_limit = 137438953472
  

• Set a user variable

  SET @@your_variable_name = your_variable_value;