Work Music

soma fm → Streams. Ambient streams. Keeps the hands typing and the brain coding.

In AAC format, as well as the older MP3. iTunes-friendly links.

One stream in particular works for me: "Mission Control" where ambient music is ingeniously overlaid with the chatter patter of real NASA mission control personnel and astronauts -- sometimes live, sometimes recorded.

Location of Postgres Logs on a Mac

For Postgres 9.0.4 on Mac OS X 10.6.7, I found logs here:

  /Library/PostgreSQL/9.0/data/pg_log

Accessing Postgres On The Command-Line on Mac OS X

I simply wanted to restart the Postgres server. I'm trying to enable SSL/TLS, and such settings are checked only when Postgres starts. Postgres is set to auto-start when the Mac boots, if you install using EnterpriseDB's free Mac installer.  But I want to restart Postgres manually, without rebooting the Mac.

You'd think restarting Postgres would be easy, but no. The pgAdmin program is not built to stop or start the Postgres server, at least not that I could find. The command line tool "pg_ctl" can check the status of a server as well as start and stop. That command even has a handy "restart" option that effectively does both the stop and start. But I cannot run that pg_ctl from my own command-line in the Terminal app. The command must be run as the 'postgres' unix user created by the Postgres installer.

So, the answer is simple, right? Run the command as "sudo", the superuser? That usually is the answer with Mac command-line limitations. But, no, not in this case. The command must be run as another user, not just with enhanced privileges. So a bit of googling might lead you to use the "su" command to act as another user, like this:

  su postgres

This fails though I don't know understand why. After much googling, I finally found the trick:

  sudo su - postgres

It takes the combination of "sudo" and "su". Also notice the hyphen with spaces.

Now I can (I mean 'postgres user can) run Postgres utility programs. The next problem is that those utilities are not found automatically from the command line. So instead of just typing "pg_ctl" in the Terminal, type the entire path to the program, such as:
  /Library/PostgreSQL/9.0/bin/pg_ctl

Tip: Rather than type, just find the programs in the Finder (or the very handy Path Finder app), then drag-and-drop to the Terminal app.

Yet another problem to solve. Some of those commands need to know where the Postgres "data" folder is. Again, you can drag and drop the path, or use Path Finder's Copy Path > Unix menu item.

So for example, to check the status of the Postgres server, run these two lines in the Terminal. Run them separately, one after the other.

  sudo su - postgres
  /Library/PostgreSQL/9.0/bin/pg_ctl status -D /Library/PostgreSQL/9.0/data

To avoid including the full paths, you can tell your Mac to include those folders when looking for programs. But that’s a topic for another day.

I'm using Postgres 9.0.4 on Mac OS X 10.6.7.

I Wish Postgres Had…

Here is my wish list for Postgres features.

• Feedback system
  I have yet to learn how to submit bugs & feature requests to the Postgres developers. So if anyone knows how I should relay this list, please post a comment to tell me.
• Multiply String function
  It can be surprisingly handy to have a command that takes a string, repeats that string a certain number of times, and returns the result. One usage is padding a string with spaces, underscores, or periods, as seen in a book's Table Of Contents. The command could be added to this collection, and might look like this:
  Multiply( string, numberOfTimes ) --> String

Postgres Server Settings

Postgres has hundreds of settings in its configuration. Nearly all of them have defaults appropriate to most of us most of the time. Here's a few you may want to consider changing.

These settings are found in the pgAdmin app menu Tools > Server Configuration > postgresql.conf.

• superuser_reserved_connections

Sets aside a few of maximum number of connections for use only by the Postgres superuser, usually named 'postgres'. Without this setting, if your server reaches its limit, you will not be able to logon as an administrator. That's not good, so turn this on and use at least the default of 3 connection slots.

Tips On Creating Login Forms

This article in Smashing Magazine has a bunch of tips and techniques to consider when building Login forms and Account Creation forms. For example, for web forms they gives alternatives to those annoying Captchas such as the Honeypot-Captcha and timestamp analysis.

Uninstalling Postgres

Dang! I lost the password to one of my Postgres installations. Fortunately, it had not been used so no great loss. But how to uninstall both the Postgres software, and the 'postgres' unix user on Mac OS X?

I found this posting telling me how to uninstall. I've written my own explanation below.

I did this with Postgres 9.0.4 with the Mac installer provided by EnterpriseDB, on Mac OS X 10.6.7 Snow Leopard.

The steps are:

1. Run the uninstaller app.
2. Delete the enclosing folder, and provide Mac system password to authorize deleting the 'data' folder.
3. Delete the 'postgres' Unix user.

Details

Run the uninstaller app installed as part of the Postgres package. However the uninstaller is not located in the Applications > PostgeSQL folder. Instead, look in the root folder (your hard disk) > Library > PostgreSQL > 9.0 > uinstall-postgresql.app. Running that app will remove all of Postgres except for two pieces:

• The folder enclosing the uninstaller, and the all-important "data" folder containing any databases you created.

The "data" folder is special because it belongs to the "postgres" Unix user created on your Mac during installation. So the admin Mac user in which you are using the Finder does not have direct access to that folder. Fortunately the regular admin Mac user can move that folder to the trash though you will be prompted for your Mac password.

• 'postgres' Unix user

Killing that Unix user, and its password, requires the use of Terminal.app found in the "Utilities" folder of the "Applications" folder.

Type the following into the Terminal:
    sudo dscl . delete /users/postgres

The 'sudo' means your are invoking special privileges as a system administrator. So you’ll be prompted to enter your Mac system password. The 'dscl' command works on Directory Service.

With that you are done. You may now reinstall Postgres. Only this time, write down your password in a safe place immediately, as I learned the hard way.

If for some reason you need/want to use the command line to unstall Postgres rather than the uninstaller app, see that posting link above.