1. 获取time_bucket的范围

SELECT toolkit_experimental.time_bucket_range('15 days'::interval, '2020-05-01');

输出：["2020-04-17 00:00:00+00","2020-05-02 00:00:00+00")

2. 设置time_bucket起始时间

select time_bucket('15 days'::interval, '2020-05-01', origin=>'2020-05-01');

3. 新建用户、库、授权

CREATE USER dbuser WITH PASSWORD 'dbuser';
CREATE DATABASE exampledb OWNER dbuser;
GRANT ALL PRIVILEGES ON DATABASE exampledb TO dbuser;

4. 查询当前正在执行中的select语句

SELECT
	procpid,
	START,
	now( ) - START AS lap,
	current_query 
FROM
	(
	SELECT
		backendid,
		pg_stat_get_backend_pid ( S.backendid ) AS procpid,
		pg_stat_get_backend_activity_start ( S.backendid ) AS START,
		pg_stat_get_backend_activity ( S.backendid ) AS current_query 
	FROM
		( SELECT pg_stat_get_backend_idset ( ) AS backendid ) AS S 
	) AS S 
WHERE
	current_query LIKE'%SELECT *%' 
ORDER BY
	lap DESC;