PostgreSQL: don't use async_exec and async_query with postgres-pr. Closes #7727.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6346 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

@@ -1,5 +1,7 @@
 *SVN*
 
+* PostgreSQL: don't use async_exec and async_query with postgres-pr.  #7727 [flowdelic]
+
 * Fix has_many :through << with custom foreign keys.  #6466, #7153 [naffis, Rich Collins]
 
 * Test DateTime native type in migrations, including an edge case with dates

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -55,7 +55,10 @@ module ActiveRecord
       def initialize(connection, logger, config = {})
         super(connection, logger)
         @config = config
-        @async = config[:allow_concurrency]
+
+        # Ignore async_exec and async_query with the postgres-pr client lib.
+        @async = config[:allow_concurrency] && @connection.respond_to(:async_exec)
+
         configure_connection
       end