diff --git a/elasticsearch/connection/pooling.py b/elasticsearch/connection/pooling.py
index 58641101..2c225aa1 100644
--- a/elasticsearch/connection/pooling.py
+++ b/elasticsearch/connection/pooling.py
@@ -1,22 +1,14 @@
+from Queue import Queue
 from .base import Connection
 
+
 class PoolingConnection(Connection):
     def __init__(self, *args, **kwargs):
-        self._max_pool_size = kwargs.pop('max_connection_pool_size', 50)
-        self._free_connections = []
-        self._in_use_connections = set()
+        self._free_connections = Queue()
         super(PoolingConnection, self).__init__(*args, **kwargs)
 
     def _get_connection(self):
-        try:
-            con = self._free_connections.pop()
-        except IndexError:
-            con = self._make_connection()
-
-        self._in_use_connections.add(con)
-        return con
+        return self._make_connection() if self._free_connections.empty() else self._free_connections.get()
 
     def _release_connection(self, con):
-        self._in_use_connections.remove(con)
-        self._free_connections.append(con)
-
+        self._free_connections.put(con)
\ No newline at end of file
diff --git a/elasticsearch/connection/thrift.py b/elasticsearch/connection/thrift.py
index f0d92b2a..ff9bde02 100644
--- a/elasticsearch/connection/thrift.py
+++ b/elasticsearch/connection/thrift.py
@@ -65,9 +65,9 @@ class ThriftConnection(PoolingConnection):
         except (TException, SocketTimeout) as e:
             self.log_request_fail(method, url, body, time.time() - start, exception=e)
             raise ConnectionError('N/A', str(e), e)
-        finally:
-            if tclient:
-                self._release_connection(tclient)
+
+        if tclient:
+            self._release_connection(tclient)
 
         if not (200 <= response.status < 300) and response.status not in ignore:
             self.log_request_fail(method, url, body, duration, response.status)