Fixed bug when a connection pool internally makes an attempt to ping a

closed connection (#482).

Author: anthony-tuininga

doc/src/release_notes.rst

@@ -22,6 +22,9 @@ Thin Mode Changes
 #)  Emulate support for :meth:`Queue.deqmany()` with JSON payloads when using
     Oracle Database 21c by internally calling :meth:`Queue.deqone()` as many
     times as needed.
+#)  Fixed bug when a connection pool internally makes an attempt to ping a
+    closed connection
+    (`issue 482 <https://github.com/oracle/python-oracledb/issues/482>`__).
 #)  Fixed bug when connecting with asyncio using the parameter ``https_proxy``.
 #)  Fixed regression when connecting where only the host specified by the
     ``https_proxy`` parameter can successfully perform name resolution.

src/oracledb/impl/thin/packet.pyx

@@ -660,10 +660,13 @@ cdef class ReadBuffer(Buffer):
         cdef:
             bint notify_waiter
             Packet packet
-        packet = self._transport.read_packet()
-        self._process_packet(packet, &notify_waiter, False)
-        if notify_waiter:
-            self._start_packet()
+        packet = self._transport.read_packet(raise_exc=False)
+        if packet is None:
+            self._pending_error_num = TNS_ERR_SESSION_SHUTDOWN
+        else:
+            self._process_packet(packet, &notify_waiter, False)
+            if notify_waiter:
+                self._start_packet()
 
     cdef bint has_response(self):
         """

src/oracledb/impl/thin/transport.pyx

@@ -332,7 +332,7 @@ cdef class Transport:
         self._transport = transport
         self._transport_num = sock.fileno()
 
-    cdef Packet read_packet(self):
+    cdef Packet read_packet(self, bint raise_exc=True):
         """
         Reads a packet from the transport.
         """
@@ -344,10 +344,15 @@ cdef class Transport:
             try:
                 data = self._transport.recv(self._max_packet_size)
             except ConnectionResetError as e:
+                self._transport = None
+                if not raise_exc:
+                    return None
                 errors._raise_err(errors.ERR_CONNECTION_CLOSED, str(e),
                                   cause=e)
             if len(data) == 0:
                 self.disconnect()
+                if not raise_exc:
+                    return None
                 errors._raise_err(errors.ERR_CONNECTION_CLOSED)
             packet = self.extract_packet(data)
         return packet