Error installing pg, requires Ruby version >= 2.2

Question

gem install pg
ERROR:  Error installing pg:
pg requires Ruby version >= 2.2.

This happened after I installed a newer version of PG on my system, so I figure that's fine, what's happening is that it's installing gem pg using the config from the newer version of Postgres that I installed with Homebrew.

So I figure I'll just install the gem using the older version of PG that I had before.

brew install postgresql@9.6
Error: postgresql@9.6 9.6.14 is already installed

Ok perfect! So I then located the pg_config file and am trying to install the gem pg using that config:

gem install pg -- --with-pg-config=/usr/local/Cellar/postgresql@9.6/9.6.14/bin/pg_config

ERROR:  Error installing pg:
pg requires Ruby version >= 2.2.

Yet the error persists... any help appreciated... I've tried uninstalling/reinstalling PG a number of times now...

Also something else that's super frustrating... is there a list somewhere that shows what versions of PG are compatible with which versions of Ruby? I feel like every few months I run into this problem and have this frustrating search happening...

ruby --version
> ruby 2.1.2p95 (2014-05-08 revision 45877) [x86_64-darwin13.0]
which ruby
> /Users/jamesdong/.rvm/rubies/ruby-2.1.2/bin/ruby
which gem
> /Users/jamesdong/.rvm/rubies/ruby-2.1.2/bin/gem

Answer 1

According to the Changelog , pg 1.2.0 removed support for Ruby <= 2.2. Since you're using 2.1 you'll want to gem install pg -v 1.1.4 , the previous version

(I don't think the actual postgres version you're using should matter as much, 1.1.4 appears to support at least up to 11.x)