PostgreSQL从库切换主库时遇到问问题

1. pgsql drop database: cannot drop a template database

不能删除一个模板数据库。

确认是否模板数据库：

t: 是模板数据库
f：不是

postgres=# select datname, datistemplate from pg_database where datname='***db';
 datname | datistemplate 
---------+---------------
 ***db  | t
(1 row)
postgres=# update pg_database set datistemplate=false where datname='***db';
UPDATE 1
postgres=# 
postgres=# select datname, datistemplate from pg_database where datname='***db';
 datname | datistemplate 
---------+---------------
 ***db  | f
(1 row)

2. database “***db” is being accessed by other users

postgres=# drop database ***db;
ERROR:  database "***db" is being accessed by other users
DETAIL:  There is 1 other session using the database.
postgres=# select pg_terminate_backend(pg_stat_activity.pid) from pg_stat_activity where datname='***db' and pid <>pg_backend_pid();
 pg_terminate_backend 
----------------------
 t
(1 row)
postgres=# drop database ***db;
DROP DATABASE