PostgreSQL pg_tblspc Missing After macOS Update (Yosemite, El Capitan)

The Problem:

• You're using PostgreSQL, a database management system, on macOS.
• You installed a new version of macOS (Yosemite or El Capitan in this case).
• After the update, you notice the pg_tblspc directory is missing. This directory is crucial for storing PostgreSQL data.

Why it Happens:

• Sometimes, major macOS updates can unintentionally remove or alter files during the upgrade process.
• In this instance, the update might have removed the pg_tblspc directory within the PostgreSQL data directory.

Homebrew Connection:

• Homebrew is a popular package manager for macOS.
• It's possible you installed PostgreSQL using Homebrew.
• While Homebrew itself isn't directly causing the issue, it might be the way you manage PostgreSQL on your system.

Solutions:

1. Recreate the Directory:

   • This is a simple fix. You can manually recreate the pg_tblspc directory within the PostgreSQL data directory (usually located at /usr/local/var/postgres).

2. Reinitialize PostgreSQL:

   • This is a more comprehensive approach. It involves stopping the PostgreSQL service, backing up your data (important!), and then reinitializing the PostgreSQL database cluster. This will recreate all the necessary directories, including pg_tblspc.

Choosing the Right Solution:

• Recreating the directory is a quicker solution if you're comfortable and have no data corruption concerns.
• Reinitializing PostgreSQL is a cleaner approach, especially if you suspect other data directory issues. However, remember to back up your data first!

Additional Notes:

• This issue seems to be specific to older macOS versions (Yosemite and El Capitan).
• It's always recommended to check the official PostgreSQL documentation for the latest installation and upgrade instructions for your specific macOS version.

# Check if pg_tblspc directory exists
if [ ! -d /usr/local/var/postgres/pg_tblspc ]; then
  echo "pg_tblspc directory is missing!"

  # Recreate the directory (use sudo if necessary)
  sudo mkdir /usr/local/var/postgres/pg_tblspc
  echo "pg_tblspc directory recreated."
fi

Explanation:

1. The script starts with an if statement.
2. The [ ! -d /usr/local/var/postgres/pg_tblspc ] checks if the directory /usr/local/var/postgres/pg_tblspc doesn't exist (! -d).
3. If the directory is missing, the script echoes a message.
4. Then, it uses sudo mkdir to create the directory (replace sudo with your preferred method if it doesn't require superuser privileges).
5. Finally, it echoes a success message if the directory is recreated.

Remember:

• This is a basic example. Always ensure you have proper backups before making any changes to your PostgreSQL data directory.
• Refer to the official PostgreSQL documentation for your specific version for detailed instructions on reinitializing the database if that's your chosen solution.

Use initdb (if reinstalling PostgreSQL is acceptable):

• This approach involves reinstalling PostgreSQL, which will recreate the necessary directories including pg_tblspc. However, it's important to note that this will erase any existing databases unless you have backups.

Here's a general guideline (refer to official documentation for specifics):

• Stop the PostgreSQL service: Use the appropriate command for your system (e.g., pg_ctl stop).
• Back up your existing databases: Use tools like pg_dump to create backups of your databases before proceeding.
• Reinitialize the PostgreSQL cluster: Use the initdb command with the -D flag specifying the desired data directory location (e.g., initdb -D /usr/local/var/postgres). This will recreate the directory structure and initialize a new cluster.
• Restore your databases (optional): If you have backups, use psql and pg_restore to import them into the newly initialized cluster.
• Start the PostgreSQL service: Use the appropriate command for your system (e.g., pg_ctl start).

Check for Alternative Data Directory (if using Homebrew):

• If you installed PostgreSQL using Homebrew, the data directory location might differ from the default.

  • Check your Homebrew configuration for PostgreSQL. You can use brew info postgresql to see the installed formula details. Look for a section mentioning data directory or configuration file location.
  • If the formula specifies a custom data directory, navigate to that location and see if pg_tblspc exists there.