How to upgrade PostgreSQL from 12 to 13

Juraj Kostolanský October 21, 2020

If you are upgrading to PostgreSQL 14, please use the new tutorial. There are some important changes in the process.


The new PostgreSQL 13 has been released. There are multiple ways to upgrade from the old version 12, and the easiest one is by using the pg_upgrade tool. Here is a quick tutorial for Ubuntu (or Debian) systems. And, please, do not forget to back up your data!

Update packages and install the new PostgreSQL 13.

sudo apt-get update
sudo apt-get install postgresql-13 postgresql-server-dev-13

Check if there are any differences in the config files.

diff /etc/postgresql/12/main/postgresql.conf /etc/postgresql/13/main/postgresql.conf
diff /etc/postgresql/12/main/pg_hba.conf /etc/postgresql/13/main/pg_hba.conf

Stop the PostgreSQL service.

sudo systemctl stop postgresql.service

Log in as the postgres user.

sudo su - postgres

Check clusters (notice the --check argument, this will not change any data).

/usr/lib/postgresql/13/bin/pg_upgrade \
  --old-datadir=/var/lib/postgresql/12/main \
  --new-datadir=/var/lib/postgresql/13/main \
  --old-bindir=/usr/lib/postgresql/12/bin \
  --new-bindir=/usr/lib/postgresql/13/bin \
  --old-options '-c config_file=/etc/postgresql/12/main/postgresql.conf' \
  --new-options '-c config_file=/etc/postgresql/13/main/postgresql.conf' \
  --check

Migrate the data (without the --check argument).

/usr/lib/postgresql/13/bin/pg_upgrade \
  --old-datadir=/var/lib/postgresql/12/main \
  --new-datadir=/var/lib/postgresql/13/main \
  --old-bindir=/usr/lib/postgresql/12/bin \
  --new-bindir=/usr/lib/postgresql/13/bin \
  --old-options '-c config_file=/etc/postgresql/12/main/postgresql.conf' \
  --new-options '-c config_file=/etc/postgresql/13/main/postgresql.conf'

Go back to the regular user.

exit

Swap the ports for the old and new PostgreSQL versions.

sudo vim /etc/postgresql/13/main/postgresql.conf
# ...and change "port = 5433" to "port = 5432"

sudo vim /etc/postgresql/12/main/postgresql.conf
# ...and change "port = 5432" to "port = 5433"

Start the PostgreSQL service.

sudo systemctl start postgresql.service

Log in as the postgres user again.

sudo su - postgres

Check the new PostgreSQL version.

psql -c "SELECT version();"

Run the generated analyze_new_cluster script.

./analyze_new_cluster.sh

Back to normal user.

exit

Check which old PostgreSQL packages are installed.

apt list --installed | grep postgresql

Remove the old PostgreSQL packages (from the listing above).

sudo apt-get remove postgresql-12 postgresql-server-dev-12

Remove the old configuration.

sudo rm -rf /etc/postgresql/12/

Log in as the postgres user once more.

sudo su - postgres

Finally, drop the old cluster data.

./delete_old_cluster.sh

Done!

PS: This tutorial works also perfectly well with the older PostgreSQL 11.

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