session_start hangs

Question

since a few hours our server hangs every time you do a session_start.

For testing purposes i created a script which looks like this:

Answer 1

If you use pgAdmin 4 this can happen as well.

If you have File > Preferences > SQL Editor > Options > "Auto Commit" disabled, and you just ran a query using the query tool but didn't manually commit, then session_start() will freeze.

Enable auto commit, or manually commit, or just close pgAdmin, and it will no longer freeze.