如何在Mac上安装Postgres 9.4？无法找到相关细节，求指引

Hey there, I totally get it—tracking down an older PostgreSQL version like 9.4 on Mac can feel like searching for a needle in a haystack, since most official channels prioritize the latest releases these days. Let me walk you through two reliable methods to get it up and running:

Homebrew is a go-to for Mac package management, and even though 9.4 isn't in the default repo anymore, we can still grab it:

• First, make sure your Homebrew is up to date:
  brew update
• Next, check if the 9.4 tap is still available:
  brew search postgresql@9.4
• If it shows up, install it directly:
  brew install postgresql@9.4
• If not, you'll need to pull the historical formula from Homebrew's commit history. Head to the Homebrew Core GitHub repo, find the commit that corresponds to PostgreSQL 9.4, copy its hash, and run:
  brew install https://raw.githubusercontent.com/Homebrew/homebrew-core/<YOUR_COMMIT_HASH>/Formula/postgresql.rb
• After installation, add the 9.4 binaries to your system PATH so your terminal recognizes it:
  For Zsh users:
  echo 'export PATH="/usr/local/opt/postgresql@9.4/bin:$PATH"' >> ~/.zshrc
  For Bash users:
  echo 'export PATH="/usr/local/opt/postgresql@9.4/bin:$PATH"' >> ~/.bash_profile
• Reload your shell config to apply the change:
  source ~/.zshrc (or source ~/.bash_profile for Bash)

The PostgreSQL project keeps old installers in their archive:

• Locate the Mac-specific DMG installer for 9.4 (it'll be named something like postgresql-9.4.x-osx.dmg—you can find this in the official PostgreSQL archive section)
• Download the DMG, open it, and follow the installation wizard. Make sure to note the default credentials (usually username postgres, port 5432, and a password you set during setup)
• Once installed, the files will live in /Library/PostgreSQL/9.4/. Add the bin directory to your PATH:
  echo 'export PATH="/Library/PostgreSQL/9.4/bin:$PATH"' >> ~/.zshrc (or your Bash config file)
• Reload your shell config as before.

To confirm everything worked, open a new terminal window and run:
psql --version
You should see output like psql (PostgreSQL) 9.4.x if the install was successful.

• For Homebrew installs:
  brew services start postgresql@9.4
• For official DMG installs:
  You can either use the PostgreSQL icon in System Preferences to start the service, or run this command:
  pg_ctl -D /Library/PostgreSQL/9.4/data start

内容的提问来源于stack exchange，提问作者Pubudu