Connecting to PostgreSQL without TCP/IP

[Jason Cater]

Greetings, 

I recently ran across this tiny piece of trivia about PostgreSQL clients.  If 
you specify the "host" parameter to be a directory, then the client looks for 
a sockets file in that directory.  

In the past, we have told people that in order to use PostgreSQL with GNUe, 
you would have to enable postmaster to listen for TCP/IP requests.  This is 
not true.  

To get GNUe tools to use the sockets file (which is what psql uses if you do 
not pass a -h value), your connections.conf file will look like: 

[gnue]
comment = GNUe Test
provider = pypgsql
host = /tmp
dbname = gnue

note that most installations default to PostgreSQL's sockets file being in 
/tmp.  Debian is the exception.  For a default Debian install, your file 
would look like: 

[gnue]
comment = GNUe Test
provider = pypgsql
host = /var/run/postgresql
dbname = gnue


Note that this is true of all psql clients.  I actually discovered this when 
trying to set up a Zope installation at work. To see this in action, try: 

  psql -h /var/run/postgres

This should behave the same as a plain "psql" without any options. 

I do not know what "host=" line would be used for PostgreSQL running under Mac 
OS 8/9 or Windows. 

If you are running a single-machine setup (for example, a development 
machine), you are more than likely better off using this setup than TCP/IP as 
it is more secure (you can turn off TCP/IP listening so you aren't exposing 
your database to anything but a local client) and supposedly faster. 

-- Jason