若需要終止特定的SQL或會話來恢復(fù)系統(tǒng)狀態(tài)，先通過pg_stat_activity系統(tǒng)視圖查詢當(dāng)前的查詢：
select current_query,procpid from pg_stat_activity ;
current_query | procpid
-----------------------------------------------------+---------
select current_query,procpid from pg_stat_activity; | 32584
SELECT xxx | 32238說明
current_query為當(dāng)前正在進(jìn)行的查詢，procpid為后臺進(jìn)程的PID。
終止非當(dāng)前連接的SELECT：
SELECT pg_cancel_backend(pg_stat_activity.procpid)
FROM pg_stat_activity
WHERE procpid <> pg_backend_pid() and current_query like 'SELECT%';--注意SELECT的大小寫
pg_cancel_backend
-------------------
t
(1 rows)或
SELECT pg_terminate_backend(pg_stat_activity.procpid)
FROM pg_stat_activity
WHERE procpid <> pg_backend_pid() and current_query like 'SELECT%'; --注意SELECT的大小寫
pg_terminate_backend
-------------------
t
(1 rows)說明
cancel 和terminate僅適用于當(dāng)前用戶的查詢或權(quán)限小于等于當(dāng)前用戶的查詢。若提示"ERROR: must be superuser or rds_superuser to signal other server processes"，則說明后臺有其他用戶的連接，但不影響cancel 和terminate的執(zhí)行。