ps_is_thread_instrumented.sql

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-- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

DROP FUNCTION IF EXISTS ps_is_thread_instrumented;

DELIMITER $$

CREATE DEFINER='mysql.sys'@'localhost' FUNCTION ps_is_thread_instrumented (
        in_connection_id BIGINT UNSIGNED
    ) RETURNS ENUM('YES', 'NO', 'UNKNOWN')
    COMMENT '
Description
-----------

Checks whether the provided connection id is instrumented within Performance Schema.

Parameters
-----------

in_connection_id (BIGINT UNSIGNED):
  The id of the connection to check.

Returns
-----------

ENUM(\'YES\', \'NO\', \'UNKNOWN\')

Example
-----------

mysql> SELECT sys.ps_is_thread_instrumented(CONNECTION_ID());
+------------------------------------------------+
| sys.ps_is_thread_instrumented(CONNECTION_ID()) |
+------------------------------------------------+
| YES                                            |
+------------------------------------------------+
'

    SQL SECURITY INVOKER
    NOT DETERMINISTIC
    READS SQL DATA
BEGIN
    DECLARE v_enabled ENUM('YES', 'NO', 'UNKNOWN');

    IF (in_connection_id IS NULL) THEN
        RETURN NULL;
    END IF;

    SELECT INSTRUMENTED INTO v_enabled
      FROM performance_schema.threads 
     WHERE PROCESSLIST_ID = in_connection_id;

    IF (v_enabled IS NULL) THEN
        RETURN 'UNKNOWN';
    ELSE
        RETURN v_enabled;
    END IF;
END$$

DELIMITER ;