Relating to original question posted on Stack Overflow here.

Interested in distributing a copy of PostgreSQL with a C# app (for Windows). However, trying to understand how the following scenario should be handled:

  • PostgreSQL already installed on the user's system

From my understanding, should be possible to install a 2nd instance of PostgreSQL to run at the same time on the same computer system (as a different service, bound to a different TCP port #?). However, the closest answer for how this would be done was found here, which does not really provide a lot of detail.

So far, in my test environment (VM), I have one instance of Ver. 12 PostgreSQL installed in the default directory C:\Program Files\PostgreSQL\12.

Am I correct to understand that I should copy all of the contens of the C:\Program Files\PostgreSQL\12 directory and copy/paste to a different directory (e.g. C:\Program Files\PostgreSQL\Test12?

Then, run pg_ctl register, but with what options?

And, then after, I should run pg_ctl start?

Are there any considerations that should be made before all of this is done?


1 Answer 1


You don't need the binaries two times, you only need to create a second data directory (aka "cluster").

The following creates a new data directory under c:\ProgramData\pgdata2. I highly recommend to not put the data directory under c:\Program Files (that's one of the reasons I stopped using the EntpriseDB installer because it always suggested that)

"C:\Program Files\PostgreSQL\12\bin\initdb" -D "c:\ProgramData\pgdata2" 

Then edit c:\ProgramData\pgdata2\postgresql.conf and change the value for port, e.g.

port = 5335

Then you can register the new Windows service and provide the data directory during registration:

pg_ctl register -N other-postgres -D "c:\ProgramData\pgdata2"

Once the service is registered, you can start it using net start

net start other-postgres
  • 1
    If you don't use the EnterpriseDB installer, which one do you use?
    – Vérace
    Nov 25, 2019 at 15:48
  • 1
    @Vérace: I use the ZIP files to install Postgres I essentially do what I described in this answer (after unzipping the archive).
    – user1822
    Nov 25, 2019 at 15:48
  • Followed the steps to the T, but when trying to connect with psql with the following command: psql -h localhost -p 5433, I am getting a "connection refused." I see both port 5432 and 5433 occupied by postgres.exe (running netstat). 5432 is my original instance and 5433 is my 2nd instance.
    – Dash
    Nov 25, 2019 at 16:07
  • Face-palm I forgot to uncomment the listen_addresses = 'localhost' config. setting.
    – Dash
    Nov 25, 2019 at 16:10
  • @a_horse_with_no_name - I did that last weekend, but I was worried about any potential performance hits? I take it there aren't any?
    – Vérace
    Nov 25, 2019 at 18:49

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