SHOW VARIABLES

Function

SHOW VARIABLES displays the values of system variables. This statement does not require any privileges. It only requires the ability to connect to the server. The like and where clauses can be appended for further matching.

SHOW VARIABLES accepts the optional GLOBAL or SESSION variable range modifiers:

• With the GLOBAL modifier, the statement displays global system variable values. These are the values of the corresponding session variables used to initialize the new connection to MogDB. If the variable does not have a global value, no value is displayed.
• With the SESSION modifier, the statement displays the system variable values that are valid for the current connection.
• If the modifier is not present, the default value is SESSION.

Precautions

N/A

Syntax

SHOW [GLOBAL | SESSION] VARIABLES [LIKE 'pattern' | WHERE expr];

Parameter Description

• [GLOBAL | SESSION]

  global denotes the default value of the query guc parameter.

  session indicates the session value of the query guc parameter.

• [LIKE 'pattern' | WHERE expr]

  Matches an expression.

Examples

-- Query guc parameters beginning with v
MogDB=# show variables like 'v%';
       Variable_name        |   Value    
----------------------------+------------
 vacuum_cost_delay          | 0
 vacuum_cost_limit          | 200
 vacuum_cost_page_dirty     | 20
 vacuum_cost_page_hit       | 1
 vacuum_cost_page_miss      | 10
 vacuum_defer_cleanup_age   | 0
 vacuum_freeze_min_age      | 2000000000
 vacuum_freeze_table_age    | 4000000000
 vacuum_gtt_defer_check_age | 10000
 var_eq_const_selectivity   | off
 version_retention_age      | 0
(11 rows)