# - bof - #



# -  - #
# - Documentation - #
https://www.kostolansky.sk/posts/upgrading-to-postgresql-12/

# -  - #
# - Upgrade PostgreSQL from 11 to 12  - #
Update: This tutorial works also perfectly well with the new PostgreSQL 13.



:A
# -  - #
# - Update & install PostgreSQL 12 - #
sudo apt-get update;
sudo apt-get install postgresql-12 postgresql-server-dev-12 -y;



:B
# -  - #
# - Check differences - #
diff /etc/postgresql/11/main/postgresql.conf /etc/postgresql/12/main/postgresql.conf
diff /etc/postgresql/11/main/pg_hba.conf /etc/postgresql/12/main/pg_hba.conf



:C
# -  - #
# - Stop PostgreSQL - #
sudo systemctl stop postgresql.service;



:D
# -  - #
# - Login postgres user - #
sudo su postgres;



:E
# -  - #
# - Check clusters (notice the --check argument will not change any data - #
/usr/lib/postgresql/12/bin/pg_upgrade \
  --old-datadir=/var/lib/postgresql/11/main \
  --new-datadir=/var/lib/postgresql/12/main \
  --old-bindir=/usr/lib/postgresql/11/bin \
  --new-bindir=/usr/lib/postgresql/12/bin \
  --old-options '-c config_file=/etc/postgresql/11/main/postgresql.conf' \
  --new-options '-c config_file=/etc/postgresql/12/main/postgresql.conf' \
  --check



:F
# -  - #
# - Migrate data (without the --check argument) - #
/usr/lib/postgresql/12/bin/pg_upgrade \
  --old-datadir=/var/lib/postgresql/11/main \
  --new-datadir=/var/lib/postgresql/12/main \
  --old-bindir=/usr/lib/postgresql/11/bin \
  --new-bindir=/usr/lib/postgresql/12/bin \
  --old-options '-c config_file=/etc/postgresql/11/main/postgresql.conf' \
  --new-options '-c config_file=/etc/postgresql/12/main/postgresql.conf'



:G
# -  - #
# - Exit postgres user - #
exit



:H
# -  - #
# - Swap ports for old and new PostgreSQL - #
sudo vim /etc/postgresql/12/main/postgresql.conf
# ...and change "port = 5433" to "port = 5432"

sudo vim /etc/postgresql/11/main/postgresql.conf
# ...and change "port = 5432" to "port = 5433"



:I
# -  - #
# - Start PostgreSQL service - #
sudo systemctl start postgresql.service;



:J
# -  - #
# - Login as postgres user again - #
sudo su postgres;



:K
# -  - #
# - Check the new PostgreSQL version - #
psql -c "SELECT version();"



:L
# -  - #
# - Run generated analyze_new_cluster script - #
./analyze_new_cluster.sh



:M
# -  - #
# - Back to normal user - #
exit



:N
# -  - #
# - Check which old PostgreSQL packages are installed - #
apt list --installed | grep postgresql



:O
# -  - #
# - Remove old PostgreSQL packages - #
sudo apt remove postgresql-11 -y;
sudo apt remove postgresql-11 postgresql-server-dev-11 -y;



:P
# -  - #
# - Remove the old configuration - #
sudo rm -rf /etc/postgresql/11/



:Q
# -  - #
# - Login as postgres user once more - #
sudo su postgres;



:R
# -  - #
# - Finally, drop the old cluster data - #
./delete_old_cluster.sh



Done!



# - eof - #