The persisted_variables
table
provides an SQL interface to the
mysqld-auto.cnf
file that stores
persisted global system variable settings, enabling the file
contents to be inspected at runtime using
SELECT
statements. Variables
are persisted using
SET
PERSIST
or PERSIST_ONLY
statements; see Section 15.7.6.1, “SET Syntax for Variable Assignment”. The table
contains a row for each persisted system variable in the file.
Variables not persisted do not appear in the table.
The
SENSITIVE_VARIABLES_OBSERVER
privilege is required to view the values of sensitive system
variables in this table.
For information about persisted system variables, see Section 7.1.9.3, “Persisted System Variables”.
Suppose that mysqld-auto.cnf
looks like
this (slightly reformatted):
Press CTRL+C to copy{ "Version": 1, "mysql_server": { "max_connections": { "Value": "1000", "Metadata": { "Timestamp": 1.519921706e+15, "User": "root", "Host": "localhost" } }, "autocommit": { "Value": "ON", "Metadata": { "Timestamp": 1.519921707e+15, "User": "root", "Host": "localhost" } } } }
Then persisted_variables
has
these contents:
Press CTRL+C to copymysql> SELECT * FROM performance_schema.persisted_variables; +-----------------+----------------+ | VARIABLE_NAME | VARIABLE_VALUE | +-----------------+----------------+ | autocommit | ON | | max_connections | 1000 | +-----------------+----------------+
The persisted_variables
table has
these columns:
VARIABLE_NAME
The variable name listed in
mysqld-auto.cnf
.VARIABLE_VALUE
The value listed for the variable in
mysqld-auto.cnf
.
persisted_variables
has these
indexes:
Primary key on (
VARIABLE_NAME
)
TRUNCATE TABLE
is not permitted
for the persisted_variables
table.