[DATABASE/POSTGRESQL] 현재 연결 수 구하기

■ 현재 연결 수를 구하는 방법을 보여준다.

 

▶ 예제 코드 (SQL)

SELECT
    MAX_CONN
   ,USED
   ,RES_FOR_SUPER
   ,MAX_CONN-USED-RES_FOR_SUPER AS RES_FOR_NORMAL
FROM (SELECT COUNT(1) USED              FROM PG_STAT_ACTIVITY)                                          T1
    ,(SELECT SETTING::INT RES_FOR_SUPER FROM PG_SETTINGS WHERE NAME=$$superuser_reserved_connections$$) T2
    ,(SELECT SETTING::INT MAX_CONN      FROM PG_SETTINGS WHERE NAME=$$max_connections$$)                T3;