PostgreSQL

TL;DR
Further readings
1. Sources

TL;DR

One can store one's credentials in ~/.pgpass:

# line format => hostname:port:database:username:password`
# can use wildcards
postgres.lan:5643:postgres:postgres:BananaORama
*:*:sales:elaine:modestPassword

The credential file's permissions must be 0600, or it will be ignored.

Database roles represent both users and groups.
Roles are distinct from the OS' users and groups, and are global across the whole installation (there are no DB-specific roles).

Extensions in PostgreSQL are managed per database.

# Installation.
brew install 'postgresql@14'
sudo dnf install 'postgresql' 'postgresql-server'
sudo zypper install 'postgresql15' 'postgresql15-server'

# Set the password in environment variables.
export PGPASSWORD='securePassword'

# Set up the credentials file.
cat <<EOF > ~/'.pgpass'
postgres.lan:5643:postgres:postgres:BananaORama
*:*:sales:elaine:modestPassword
EOF
chmod '600' ~/'.pgpass'

# Set up the per-user services file.
cat <<EOF > ~/'.pg_service.conf'
[prod]
host = prod.0123456789ab.eu-west-1.rds.amazonaws.com
port = 5433
user = master
EOF

# Connect to servers via CLI client.
# If not given:
# - the hostname defaults to 'localhost';
# - the port defaults to '5432';
# - the username defaults to the current user.
psql 'my-db'
psql 'my-db' 'user'
psql 'postgresql://host:5433/my-db?sslmode=require'
psql -U 'username' -d 'my-db' -h 'hostname' -p 'port' -W
psql --host 'host.fqnd' --port '5432' --username 'postgres' --database 'postgres' --password
psql "service=prod sslmode=require"

# List available databases.
psql … --list

# Execute commands.
psql 'my-db' … -c 'select * from tableName;' -o 'out.file'
psql 'my-db' … -c 'select * from tableName;' -H
psql 'my-db' … -f 'commands.sql'

# Initialize a test DB.
pgbench -i 'test-db'
pgbench -i 'test-db' -h 'hostname' -p '5555' -U 'user'

# Create full backups of databases.
pg_dump -U 'postgres' -d 'sales' -F 'custom' -f 'sales.bak'
pg_dump --host 'host.fqnd' --port '5432' --username 'postgres' --dbname 'postgres' --password --schema-only
pg_dump … -T 'customers,orders' -t 'salespeople,performances'
pg_dump … -s --format 'custom'

# Dump users and groups to file
pg_dumpall -h 'host.fqnd' -p '5432' -U 'postgres' -l 'postgres' -W --roles-only --file 'roles.sql'
pg_dumpall -h 'host.fqnd' -p '5432' -U 'postgres' -l 'postgres' -Wrf 'roles.sql' --no-role-passwords

# Restore backups.
pg_restore -U 'postgres' -d 'sales' 'sales.bak'

# Execute commands from file
# E.g., restore from dump
psql -h 'host.fqnd' -U 'postgres' -d 'postgres' -W -f 'dump.sql' -e

# Generate scram-sha-256 hashes using only tools from PostgreSQL.
# Requires to actually create and delete users.
createuser 'dummyuser' -e --pwprompt && dropuser 'dummyuser'

# Generate scram-sha-256 hashes.
# Leverage https://github.com/supercaracal/scram-sha-256
scram-sha-256 'mySecretPassword'

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PostgreSQL

TL;DR

Further readings

Sources

4.5 KiB

Raw Blame History