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Debugging PostgreSQL Installation on macOS

psql: error: connection to server on socket “/tmp/.s.PGSQL.5432” failed: No such file or directory. If you’re a PostgreSQL user, you’ve likely encountered errors like:

If you’re a PostgreSQL user, you’ve likely encountered errors like:

psql: error: connection to server on socket "/tmp/.s.PGSQL.5432" failed: No such file or directory

But what causes these issues? Before diving into troubleshooting, let’s understand what happens during a PostgreSQL installation on macOS using Homebrew.

Understanding PostgreSQL Installation on macOS

When installed via Homebrew, PostgreSQL follows a structured setup process:

1. Installation: Homebrew installs PostgreSQL binaries, configuration files, and necessary dependencies.
2. Service Management: Homebrew services allow PostgreSQL to run in the background.
3. Data Directory Initialization: PostgreSQL requires an initialized data directory to store databases and settings.
4. User and Role Setup: PostgreSQL creates a default user and role system for database management.

What Happens Before and After Installation?

Before Installation

• Ensure Homebrew is installed (brew -v to check).
• Check for existing PostgreSQL installations:

brew list | grep postgresql

• Remove conflicting versions if necessary:

brew uninstall postgresql@<version>

Installation Process

To install PostgreSQL via Homebrew, run:

brew install postgresql@15

After installation, check the service status:

brew services list

To start PostgreSQL:

brew services start postgresql@15

Using Nix

1. Install PostgreSQL via Nix and Start PostgreSQL manually: