66 * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
77 *
88 * IDENTIFICATION
9- * $PostgreSQL: pgsql/src/backend/port/win32/signal.c,v 1.23 2010/01/02 16:57:50 momjian Exp $
9+ * $PostgreSQL: pgsql/src/backend/port/win32/signal.c,v 1.24 2010/01/31 17: 16:23 mha Exp $
1010 *
1111 *-------------------------------------------------------------------------
1212 */
@@ -275,6 +275,33 @@ pg_signal_thread(LPVOID param)
275275fConnected = ConnectNamedPipe (pipe ,NULL ) ? TRUE : (GetLastError ()== ERROR_PIPE_CONNECTED );
276276if (fConnected )
277277{
278+ HANDLE newpipe ;
279+
280+ /*
281+ * We have a connected pipe. Pass this off to a separate thread that will do the actual
282+ * processing of the pipe.
283+ *
284+ * We must also create a new instance of the pipe *before* we start running the new
285+ * thread. If we don't, there is a race condition whereby the dispatch thread might
286+ * run CloseHandle() before we have created a new instance, thereby causing a small
287+ * window of time where we will miss incoming requests.
288+ */
289+ newpipe = CreateNamedPipe (pipename ,PIPE_ACCESS_DUPLEX ,
290+ PIPE_TYPE_MESSAGE |PIPE_READMODE_MESSAGE |PIPE_WAIT ,
291+ PIPE_UNLIMITED_INSTANCES ,16 ,16 ,1000 ,NULL );
292+ if (newpipe == INVALID_HANDLE_VALUE )
293+ {
294+ /*
295+ * This really should never fail. Just retry in case it does, even though we have
296+ * a small race window in that case. There is nothing else we can do other than
297+ * abort the whole process which will be even worse.
298+ */
299+ write_stderr ("could not create signal listener pipe: error code %d; retrying\n" , (int )GetLastError ());
300+ /*
301+ * Keep going so we at least dispatch this signal. Hopefully, the call will succeed
302+ * when retried in the loop soon after.
303+ */
304+ }
278305hThread = CreateThread (NULL ,0 ,
279306 (LPTHREAD_START_ROUTINE )pg_signal_dispatch_thread ,
280307 (LPVOID )pipe ,0 ,NULL );
@@ -283,13 +310,24 @@ pg_signal_thread(LPVOID param)
283310 (int )GetLastError ());
284311else
285312CloseHandle (hThread );
313+
314+ /*
315+ * Background thread is running with our instance of the pipe. So replace our reference
316+ * with the newly created one and loop back up for another run.
317+ */
318+ pipe = newpipe ;
286319}
287320else
288- /* Connection failed. Cleanup and try again */
321+ {
322+ /*
323+ * Connection failed. Cleanup and try again.
324+ *
325+ * This should never happen. If it does, we have a small race condition until we loop
326+ * up and re-create the pipe.
327+ */
289328CloseHandle (pipe );
290-
291- /* Set up so we create a new pipe on next loop */
292- pipe = INVALID_HANDLE_VALUE ;
329+ pipe = INVALID_HANDLE_VALUE ;
330+ }
293331}
294332return 0 ;
295333}