postgres

Start PostgreSQL server

$ postgres -D [/var/lib/postgresql/data]

$ postgres -D [/var/lib/postgresql/data] -c log_statement=all

$ postgres -D [/var/lib/postgresql/data] -p [5433]

$ postgres --single -D [/var/lib/postgresql/data] [database]

$ postgres --version

postgres [-D datadir] [-p port] [-c name=value] [options]

postgres is the PostgreSQL database server process. It manages database files, handles connections, and executes SQL queries.
The server is typically started through pg_ctl or system service managers rather than directly. Direct invocation is useful for debugging or non-standard configurations.
Configuration parameters can be set on command line or in postgresql.conf. Runtime parameters control memory, connections, logging, and behavior.
Single-user mode bypasses normal startup for maintenance. It's used for recovery operations when the database won't start normally.
The data directory contains all database files. It must be initialized with initdb before first use and is not portable between major versions.
Logging options help diagnose problems. Statement logging shows all SQL. Connection logging tracks client access.

-D DIR

Data directory.

Port number.

Set runtime parameter.

Listen addresses.

Unix socket directory.

Shared buffers.

Max connections.

Single-user mode.

Disable fsync.

Describe configuration.

Show version.

postgresql.conf

Main configuration file in the data directory controlling memory allocation, connection limits, logging, query planner settings, WAL behavior, and replication.

Host-based authentication file controlling which users can connect from which hosts using which authentication methods (trust, md5, scram-sha-256, cert).

User name mapping file for external authentication systems, mapping OS usernames to PostgreSQL roles.

Environment variable specifying the data directory path, used as default when -D is not provided.

Running directly bypasses service management. Data directory must be secure. Configuration affects performance significantly. Major version upgrades need pg_upgrade.

PostgreSQL development began at UC Berkeley in 1986 as POSTGRES (Post-Ingres). The open-source PostgreSQL project started in 1996. It's now one of the most advanced open-source databases.

pg_ctl(1), initdb(1), psql(1), pg_dump(1)