我们开发了一个应用程序，该应用程序的后端是PostgreSQL。我收到了一个错误，比如我的应用程序丢失了数据库连接，当我检查它时，我在PostgreSQL日志中看到以下日志
2018-03-07 06:35:14 UTC [1676-2] LOG: received fast shutdown request
2018-03-07 06:35:14 UTC [1676-3] LOG: aborting any active transactions
2018-03-07 06:35:14 UTC [1620-1] postgres@db_prod FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [32367-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [7601-569] postgres@watchtower_db_prod FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [1689-2] LOG: autovacuum launcher shutting down
2018-03-07 06:35:14 UTC [7598-1] postgres@db_prod FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [30875-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [12717-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [12695-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [7956-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [23056-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [19989-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [19993-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [19988-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [19976-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [19990-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [19681-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [20474-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [19669-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [13315-1] postgres@stg FATAL: terminating connection due to administrator command
2018-03-07 06:35:14 UTC [1686-1] LOG: shutting down
2018-03-07 06:35:16 UTC [1686-2] LOG: database system is shut down
2018-03-07 06:35:17 UTC [2819-1] LOG: database system was shut down at 2018-03-07 06:35:16 UTC
2018-03-07 06:35:17 UTC [2819-2] LOG: MultiXact member wraparound protections are now enabled
2018-03-07 06:35:17 UTC [2818-1] LOG: database system is ready to accept connections
2018-03-07 06:35:17 UTC [2823-1] LOG: autovacuum launcher started
我的问题是为什么在这个自动真空过程中会发生PostgreSQL重启？