knowledge-base/KB/Linux/Server/PostgreSQL.md

creation date	tags
2022-01-08	note linux postgres database postgresql psql archlinux

Commonly used

-- list all users
\du

-- list all databases
\l

-- list all (public.) tables in a db
\dt+

-- create db
CREATE DATABASE yourdbname;

-- new user/new db
CREATE USER youruser WITH ENCRYPTED PASSWORD 'yourpass';
GRANT ALL PRIVILEGES ON DATABASE yourdbname TO youruser;

-- existing db
GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO youruser;
GRANT ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public TO youruser;
REASSIGN OWNED BY olduser TO newuser;

-- change owner
ALTER DATABASE name OWNER TO youruser;

-- revoke from old user
revoke all privileges on database db from "olduser";

-- rename db
ALTER DATABASE db RENAME TO newdb;

-- drop all owned
DROP OWNED BY <user>

-- revoke and drop
REVOKE ALL PRIVILEGES ON ALL TABLES IN SCHEMA public FROM <user>;
REVOKE ALL PRIVILEGES ON ALL SEQUENCES IN SCHEMA public FROM <user>;
REVOKE ALL PRIVILEGES ON ALL FUNCTIONS IN SCHEMA public FROM <user>;
DROP USER <user>;

Updating major versions

systemctl start postgresql.service // if not already running
chown postgres:postgres /var/lib/postgres
sudo -i -u postgres
pg_dumpall >> old_backup.sql
exit
systemctl stop postgresql.service
mv /var/lib/postgres/data /var/lib/postgres/olddata
pacman -Syyu
mkdir /var/lib/postgres/data
chown postgres:postgres /var/lib/postgres/data
sudo -i -u postgres
initdb --locale $LANG -E UTF8 -D '/var/lib/postgres/data'
exit
systemctl daemon-reload
systemctl start postgresql.service
sudo -i -u postgres
psql -f old_backup.sql postgres // if postgis is used, the lib has to be accessible before importing
exit

Updating major versions in docker(-compose)

• Backup existing instance:

  // host
  docker-compose down
  cp -r <data-dir> <data-dir-bak>
  docker-compose up -d
  docker exec -it <container-name> /bin/bash
  
  // container
  pg_dumpall >> /old_backup.sql
  exit
  
  // host
  docker cp <container-name>:/old_backup.sql .
  docker-compose down
  rm -rf <data-dir>
  

• Change major version tag of container, e.g. edit docker-compose

• Restore old database dump

  // host
  docker-compose up -d
  docker cp old_backup.sql <container-name>:/old_backup.sql
  docker exec -it <container-name> /bin/bash
  
  // container (leave out -U if chowned in container user is the correct one)
  psql -U <user-access-to-postgres, e.g. postgres> -f old_backup.sql
  rm /old_backup.sql
  exit
  
  // host
  docker-compose down
  docker-compose up -d
  

• Verify applications and delete <data-dir-bak> and the dumped .sql file