PostgreSQL modifies the maximum number of connections

1. Suitable maximum number of connections
Used_connections/max_connections is around 85%.
2. Modify the maximum number of connections
PostgreSQL Maximum number of connections defaults to 100
1) Open PostgreSQL configuration file
Vim/var/lib/pgsql/9.4/data/postgresql.conf
2) Modify the maximum number of connections
max_connections = 100
3) Restart the PostgreSQL service
In the CentOS 6.x system
Service postgresql-9.4 Restart
In the CentOS 7 system
Systemctl Restart postgresql-9.4

PostgreSQL modifies the maximum number of connections