Added psycopg2cffi dialect

1 files changed, 14 insertions, 3 deletions

diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
index fe27da8b6..5246abf1c 100644
--- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py
+++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py
@@ -512,9 +512,19 @@ class PGDialect_psycopg2(PGDialect):
         import psycopg2
         return psycopg2
 
+    @classmethod
+    def _psycopg2_extensions(cls):
+        from psycopg2 import extensions
+        return extensions
+
+    @classmethod
+    def _psycopg2_extras(cls):
+        from psycopg2 import extras
+        return extras
+
     @util.memoized_property
     def _isolation_lookup(self):
-        from psycopg2 import extensions
+        extensions = self._psycopg2_extensions()
         return {
             'AUTOCOMMIT': extensions.ISOLATION_LEVEL_AUTOCOMMIT,
             'READ COMMITTED': extensions.ISOLATION_LEVEL_READ_COMMITTED,
@@ -536,7 +546,8 @@ class PGDialect_psycopg2(PGDialect):
         connection.set_isolation_level(level)
 
     def on_connect(self):
-        from psycopg2 import extras, extensions
+        extras = self._psycopg2_extras()
+        extensions = self._psycopg2_extensions()
 
         fns = []
         if self.client_encoding is not None:
@@ -586,7 +597,7 @@ class PGDialect_psycopg2(PGDialect):
     @util.memoized_instancemethod
     def _hstore_oids(self, conn):
         if self.psycopg2_version >= (2, 4):
-            from psycopg2 import extras
+            extras = self._psycopg2_extras()
             oids = extras.HstoreAdapter.get_oids(conn)
             if oids is not None and oids[0]:
                 return oids[0:2]