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Matthew Rankin
Asked: 2010-03-02 05:40:01 +0800 CST

Determining PostgreSQL's port

  • 772

I know that by default PostgreSQL listens on port 5432, but what is the command to actually determine PostgreSQL's port?

Configuration: Ubuntu 9.10 with PostgreSQL 8.4

ubuntu port postgresql ubuntu-9.10

6 Answers

  1. Best Answer

    lsof and nmap are solutions, but they're not installed by default. What you want is netstat(8).

    sudo netstat -plunt |grep postgres
    • 37

  2. The PostgreSQL utility pg_lsclusters shows information about the configuration and status of all clusters, including the port number. 

    $ pg_lsclusters
Version Cluster   Port Status Owner    Data directory                     Log file
8.4     main      5433 online postgres /var/lib/postgresql/8.4/main       /var/log/postgresql/postgresql-8.4-main.log

    This also has the advantage of not requiring 'sudo' privileges to run.

    On Debian and Ubuntu systems, the pg_lsclusters command is provided by the package postgresql-common, which should be installed by default with the postgresql server.

    • 14

  3. If you want to do it from inside the database, just do "SHOW port". But that assumes you've been able to connect to it, at least locally...

    • 5

  4. If you are searching on the local machine, I would use the lsof command to check for the port postgresql is using

    lsof -p <postgres_process_id>
    • 2

  5. I have machines with multiple postgres instances running -- and so I also have the issue of trying to match up the correct database with each port. I tend to do:

    $ ps aux | grep  postgres | grep -v 'postgres:'

    And then, for each of instances returned look for the directory (-D argument) and:

    $ sudo grep port $DIR/postgresql.conf
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  6. Here's one solution that I've found:

    sudo apt-get install nmap
sudo nmap localhost | grep postgresql

    If you're wanting to search a non-local machine, just change localhost to the server's IP address.

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