WALをスタンバイサーバへ転送する事で高可用性と読取に対するスケールアウトを実現するストリーミングレプリケーションを作成

yum -y install epel-release centos-release-scl

yum -y install https://download.postgresql.org/pub/repos/yum/reporpms/EL-7-x86_64/pgdg-redhat-repo-latest.noarch.rpm
yum -y install https://download.postgresql.org/pub/repos/yum/reporpms/EL-8-x86_64/pgdg-redhat-repo-latest.noarch.rpm

yum -y install postgresql13-contrib postgresql13-devel

systemctl enable postgresql-13.service
systemctl disable postgresql-13.service

mkdir /data/
chown postgres:postgres /data/
chmod 750 /data/

# grep Environment=PGDATA /usr/lib/systemd/system/postgresql-13.service
Environment=PGDATA=/var/lib/pgsql/13/data/
↓
Environment=PGDATA=/data/

systemctl daemon-reload

PGSETUP_INITDB_OPTIONS="-E UTF8 --no-locale" /usr/pgsql-13/bin/postgresql-13-setup initdb

cat << __EOM__ | tee /var/lib/pgsql/.pgsql_profile
PATH=/usr/pgsql-13/bin:$PATH
export PATH
__EOM__

source /var/lib/pgsql/.pgsql_profile

# vi /var/lib/pgsql/.bash_profile
#PGDATA=/var/lib/pgsql/12/data
PGDATA=/data

source /var/lib/pgsql/.bash_profile

# su - postgres
$ psql
alter role postgres with password 'new_password';

systemctl status postgresql-13.service

-bash-4.2$ psql -V
psql (PostgreSQL) 13.7
-bash-4.2$ psql -l
                             List of databases
   Name    |  Owner   | Encoding | Collate | Ctype |   Access privileges
-----------+----------+----------+---------+-------+-----------------------
 postgres  | postgres | UTF8     | C       | C     |
 template0 | postgres | UTF8     | C       | C     | =c/postgres          +
           |          |          |         |       | postgres=CTc/postgres
 template1 | postgres | UTF8     | C       | C     | =c/postgres          +
           |          |          |         |       | postgres=CTc/postgres
(3 rows)

-bash-4.2$ createuser --login --pwprompt testuser
Enter password for new role:
Enter it again:
-bash-4.2$ createdb --owner=testuser testdb

vi /data/postgresql.conf

#listen_addresses = 'localhost'
↓
listen_addresses = '*'

vi /data/pg_hba.conf

↓追加
host    all             all             172.16.0.0/24            scram-sha-256

# systemctl reload postgresql-13.service

# pg_basebackup -R -D /data/ -h 172.16.0.114 -U postgres
# pg_basebackup -R -D /data/ -h 172.16.0.172 -U postgres

Secondaryは下記を追加
/data/postgresql.auto.conf
primary_conninfo = へ追加 application_name=postgresql

## Secondaryは下記をコメントアウト
# grep synchronous_standby_names  /data/postgresql.conf
synchronous_standby_names = 'postgresql'	# standby servers that provide sync rep

インストール
https://qiita.com/mkyz08/items/e9316fecd57bff6679cd

pgpool-IIについて
https://qiita.com/tom-sato/items/c01d4df39a6bb19e2b17

動作モード　master_slave_mode master_slave_sub_mode stream
https://www.pgpool.net/docs/pgpool-II-4.0.4/ja/html/runtime-config-running-mode.html

ロジカルレプリケーション　ストリーミングレプリケーション違い
https://www.sraoss.co.jp/tech-blog/pgsql/logical-replication-1/