(Optional) Initializing and Starting PostgreSQL

Initialize and start the PostgreSQL database as user postgres, set the user password, and configure remote management. If the PostgreSQL primary/secondary deployment environment has been prepared, skip this section.

Switch to user postgres.
```
su - postgres
```

Initialize and start the database as the postgres user.

rm -rf /data/pg-13.2/data/*
/usr/local/pgsql-13.2/bin/initdb -D /data/pg-13.2/data
/usr/local/pgsql-13.2/bin/pg_ctl -D /data/pg-13.2/data -l logfile start

Set the password of the database user postgres. This document uses the password 123456 as an example. For security purposes, please use a more complex and secure password in the production environment.
1. Log in to the database.
```
/usr/local/pgsql-13.2/bin/psql -U postgres
```
2. Set the password of the database user postgres.
```
alter user postgres with password '123456';
```
3. Exit the database.
```
\q
```
Configure remote management.
Modify the pg_hba.conf and postgresql.conf files to allow users to remotely manage the database through password authentication from any IP address.
1. Modify the pg_hba.conf file to allow all users to remotely manage all databases.
  1. Open the file.
```
vi /data/pg-13.2/data/pg_hba.conf
```
  2. Press i to enter the insert mode and add the following content to the end of the file:
```
host    all             all             0.0.0.0/0               password
```
  3. Press Esc, type :wq!, and press Enter to save the file and exit.
2. Modify the postgresql.conf file to enable functions such as remote connection and replication.
  1. Open the postgresql.conf file.
```
vi /data/pg-13.2/data/postgresql.conf
```
  2. Press i to enter the insert mode and add the following settings to the end of the file:
```
listen_addresses = '*' # This parameter specifies the IP address to be listened by the PostgreSQL service. If set to *, the server listens to all available IP addresses, including IPv4 and IPv6 addresses, and can receive connections from any client IP address connected to the server.
port = 5432 # This parameter specifies the listening port number of the PostgreSQL service, with the default value of 5432.
wal_level = replica
wal_keep_size = 1000
max_slot_wal_keep_size = 10
wal_sender_timeout = 120s
max_wal_senders = 10
min_wal_size = 800MB
archive_mode = on
archive_command = 'cp %p /data/pg-13.2/archive/%f'
hot_standby = on
max_standby_streaming_delay = 30s
wal_receiver_status_interval = 10s
hot_standby_feedback = on
max_connections = 200 # This parameter specifies the maximum number of concurrent connections allowed by the database server.
wal_log_hints = on
```
    Check the description of other parameters in the PostgreSQL configuration file on the PostgreSQL official website.
    - For parameters in the PostgreSQL 13 configuration file, see https://www.postgresql.org/docs/13/runtime-config.html.
    - For parameters in the PostgreSQL 15 configuration file, see https://www.postgresql.org/docs/15/runtime-config.html.
  3. Press Esc, type :wq!, and press Enter to save the file and exit.
3. Run the following command to restart the database for the configurations to take effect:
```
/usr/local/pgsql-13.2/bin/pg_ctl -D /data/pg-13.2/data -l logfile restart
```

Parent topic: Deployment Environment