解决方案:
执行如下指令进入PostgreSQL控制台:
sudo -u postgres psql postgres
然后在PostgreSQL控制下按顺序执行如下指令:
update pg_database set datallowconn = TRUE where datname = 'template0';
c template0
update pg_database set datistemplate = FALSE where datname = 'template1';
drop database template1;
create database template1 with template = template0 encoding = 'UTF8';
update pg_database set datistemplate = TRUE where datname = 'template1';
c template1
update pg_database set datallowconn = FALSE where datname = 'template0';
(按组合键 Ctrl-D退出PostgreSQL控制台),完毕!