Manifold doesn't even try to connect to PostgreSQL DB / AWS RDS

Question

I have a fresh install of Manifold 9 on a Windows 2016 EC2 host in Amazon EC2.

There is a PostgreSQL server (really an Amazon RDS but that's not important) and I have a hostname, username, password, and a database name. These have been tested and confirmed correct.

However following the how-to at https://manifold.net/doc/mfd9/connect_to_postgresql.htm the "test connection" fails. And it fails immediately.

I ran wireshark and confirmed that no packets were sent anywhere on port 5432 OR on any port to the known IP of the database.

Ergo, the software is telling lies and not even trying?

• Vince: This screams "DLL Issue!"
• Criggie: @vince Yes, main point of sharing this is it took time and effort to resolve, and search results were unhelpful. Hopefully this helps future users get there quicker.

Answer 1

The solution was indicated by pressing ^L to turn on the Logging Pane in Manifold.

That showed an error about "Unable to load libpq.dll" which looked to be PSQL related. It was.

1. Download and install the Postgres 11 for windows installer from https://www.postgresql.org/download/windows/
   you can untick the postgres server, don't need that.
2. Then we need to add the postgres install directory to the PATH environment variable. Open the control panel --> System --> Advanced --> Environment Variables.
   This gives two panes, click "PATH" in the lower window titled "System Variables" and then the lower [edit] button.
   Screenshot of Environment Variables pane
3. Click [New] and type in C:\Program Files\PostgreSQL11円\bin for the default, or whereever you installed it. Order is not that important.
   enter image description here
4. Finally, stop and start Manifold.exe

At this point re-add the new data source like in the PDF linked in question, and you should see a success when using the TEST button.
enter image description here

If you're still having problems, test your credentials by using PGAdmin on the same host, which will test credentials, hostname, and connectivity to the database.

• Criggie: I don't normally do the "answer your own question" type posts, but this was multiple days of troubleshooting, and the provider's support model is based on paid-tokens, which seems to encourage straight-line code. How hard would it have been for Manifold to put up a clear error dialogue box saying "libpq.dll not found, did you install the PSQL package?" There was literally one single mention of libpq.dll on their entire webite.