initial exec() method is working in pg adapter

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -220,11 +220,19 @@ module ActiveRecord
         @local_tz = nil
         @table_alias_length = nil
         @postgresql_version = nil
+        @statements = Hash.new { |h,k| h[k] = "a#{h.length + 1}" }
 
         connect
         @local_tz = execute('SHOW TIME ZONE').first["TimeZone"]
       end
 
+      def clear_cache!
+        @statements.each_value do |value|
+          exec "DEALLOCATE #{value}"
+        end
+        @statements.clear
+      end
+
       # Is this connection alive and ready for queries?
       def active?
         if @connection.respond_to?(:status)
@@ -250,8 +258,14 @@ module ActiveRecord
         end
       end
 
+      def reset!
+        clear_cache!
+        super
+      end
+
       # Close the connection.
       def disconnect!
+        clear_cache!
         @connection.close rescue nil
       end
 
@@ -501,6 +515,30 @@ module ActiveRecord
         end
       end
 
+      def exec(sql, name = 'SQL', binds = [])
+        return async_exec(sql, name, binds) if @async
+
+        log(sql, name) do
+        end
+      end
+
+      def async_exec(sql, name, binds)
+        log(sql, name) do
+          unless @statements.key? sql
+            @connection.prepare @statements[sql], sql
+          end
+
+          key = @statements[sql]
+
+          # Clear the queue
+          @connection.get_last_result
+          @connection.send_query_prepared(key, [])
+          @connection.block
+          result = @connection.get_last_result
+          ActiveRecord::Result.new(result.fields, result_as_array(result))
+        end
+      end
+
       # Executes an UPDATE query and returns the number of affected tuples.
       def update_sql(sql, name = nil)
         super.cmd_tuples

activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb

@@ -5,6 +5,8 @@ module ActiveRecord
     class PostgreSQLAdapterTest < ActiveRecord::TestCase
       def setup
         @connection = ActiveRecord::Base.connection
+        @connection.exec('drop table if exists ex')
+        @connection.exec('create table ex(id serial primary key, data character varying(255))')
       end
 
       def test_table_alias_length
@@ -12,6 +14,21 @@ module ActiveRecord
           @connection.table_alias_length
         end
       end
+
+      def test_exec_no_binds
+        result = @connection.exec('SELECT id, data FROM ex')
+        assert_equal 0, result.rows.length
+        assert_equal 2, result.columns.length
+        assert_equal %w{ id data }, result.columns
+
+        string = @connection.quote('foo')
+        @connection.exec("INSERT INTO ex (id, data) VALUES (1, #{string})")
+        result = @connection.exec('SELECT id, data FROM ex')
+        assert_equal 1, result.rows.length
+        assert_equal 2, result.columns.length
+
+        assert_equal [['1', 'foo']], result.rows
+      end
     end
   end
 end