On Windows, use pgwin32_waitforsinglesocket() instead of select() to wait for

input in the stats collector.  Our select() emulation is apparently buggy
for UDP sockets :-(.  This should resolve problems with stats collection
(and hence autovacuum) failing under more than minimal load.  Diagnosis
and patch by Magnus Hagander.

Patch probably needs to be back-ported to 8.1 and 8.0, but first let's
see if it makes the buildfarm happy...

src/backend/libpq/be-secure.c

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.75 2007/01/05 22:19:29 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/libpq/be-secure.c,v 1.76 2007/01/26 20:06:52 tgl Exp $
  *
  *	  Since the server static private key ($DataDir/server.key)
  *	  will normally be stored unencrypted so that the database
@@ -275,7 +275,8 @@ rloop:
 #ifdef WIN32
 				pgwin32_waitforsinglesocket(SSL_get_fd(port->ssl),
 											(err == SSL_ERROR_WANT_READ) ?
-								   FD_READ | FD_CLOSE : FD_WRITE | FD_CLOSE);
+								   FD_READ | FD_CLOSE : FD_WRITE | FD_CLOSE,
+											INFINITE);
 #endif
 				goto rloop;
 			case SSL_ERROR_SYSCALL:
@@ -374,7 +375,8 @@ wloop:
 #ifdef WIN32
 				pgwin32_waitforsinglesocket(SSL_get_fd(port->ssl),
 											(err == SSL_ERROR_WANT_READ) ?
-								   FD_READ | FD_CLOSE : FD_WRITE | FD_CLOSE);
+								   FD_READ | FD_CLOSE : FD_WRITE | FD_CLOSE,
+											INFINITE);
 #endif
 				goto wloop;
 			case SSL_ERROR_SYSCALL:
@@ -889,7 +891,8 @@ aloop:
 #ifdef WIN32
 				pgwin32_waitforsinglesocket(SSL_get_fd(port->ssl),
 											(err == SSL_ERROR_WANT_READ) ?
-					   FD_READ | FD_CLOSE | FD_ACCEPT : FD_WRITE | FD_CLOSE);
+					   FD_READ | FD_CLOSE | FD_ACCEPT : FD_WRITE | FD_CLOSE,
+											INFINITE);
 #endif
 				goto aloop;
 			case SSL_ERROR_SYSCALL:

src/backend/port/win32/socket.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/port/win32/socket.c,v 1.16 2007/01/05 22:19:35 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/port/win32/socket.c,v 1.17 2007/01/26 20:06:52 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -114,7 +114,7 @@ isDataGram(SOCKET s) {
 }
 
 int
-pgwin32_waitforsinglesocket(SOCKET s, int what)
+pgwin32_waitforsinglesocket(SOCKET s, int what, int timeout)
 {
 	static HANDLE waitevent = INVALID_HANDLE_VALUE;
 	static SOCKET current_socket = -1;
@@ -195,7 +195,7 @@ pgwin32_waitforsinglesocket(SOCKET s, int what)
 		}
 	}
 	else
-		r = WaitForMultipleObjectsEx(2, events, FALSE, INFINITE, TRUE);
+		r = WaitForMultipleObjectsEx(2, events, FALSE, timeout, TRUE);
 
 	if (r == WAIT_OBJECT_0 || r == WAIT_IO_COMPLETION)
 	{
@@ -205,6 +205,8 @@ pgwin32_waitforsinglesocket(SOCKET s, int what)
 	}
 	if (r == WAIT_OBJECT_0 + 1)
 		return 1;
+	if (r == WAIT_TIMEOUT)
+		return 0;
 	ereport(ERROR,
 			(errmsg_internal("Bad return from WaitForMultipleObjects: %i (%i)", r, (int) GetLastError())));
 	return 0;
@@ -274,7 +276,7 @@ pgwin32_connect(SOCKET s, const struct sockaddr * addr, int addrlen)
 		return -1;
 	}
 
-	while (pgwin32_waitforsinglesocket(s, FD_CONNECT) == 0)
+	while (pgwin32_waitforsinglesocket(s, FD_CONNECT, INFINITE) == 0)
 	{
 		/* Loop endlessly as long as we are just delivering signals */
 	}
@@ -310,7 +312,8 @@ pgwin32_recv(SOCKET s, char *buf, int len, int f)
 
 	/* No error, zero bytes (win2000+) or error+WSAEWOULDBLOCK (<=nt4) */
 
-	if (pgwin32_waitforsinglesocket(s, FD_READ | FD_CLOSE | FD_ACCEPT) == 0)
+	if (pgwin32_waitforsinglesocket(s, FD_READ | FD_CLOSE | FD_ACCEPT,
+									INFINITE) == 0)
 		return -1;
 
 	r = WSARecv(s, &wbuf, 1, &b, &flags, NULL, NULL);
@@ -355,7 +358,7 @@ pgwin32_send(SOCKET s, char *buf, int len, int flags)
 
 		/* No error, zero bytes (win2000+) or error+WSAEWOULDBLOCK (<=nt4) */
 
-		if (pgwin32_waitforsinglesocket(s, FD_WRITE | FD_CLOSE) == 0)
+		if (pgwin32_waitforsinglesocket(s, FD_WRITE | FD_CLOSE, INFINITE) == 0)
 			return -1;
 	}
 

src/backend/postmaster/pgstat.c

@@ -13,7 +13,7 @@
  *
  *	Copyright (c) 2001-2007, PostgreSQL Global Development Group
  *
- *	$PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.143 2007/01/11 23:06:03 tgl Exp $
+ *	$PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.144 2007/01/26 20:06:52 tgl Exp $
  * ----------
  */
 #include "postgres.h"
@@ -1657,11 +1657,13 @@ PgstatCollectorMain(int argc, char *argv[])
 	int			len;
 	PgStat_Msg	msg;
 
+#ifndef WIN32
 #ifdef HAVE_POLL
 	struct pollfd input_fd;
 #else
 	struct timeval sel_timeout;
 	fd_set		rfds;
+#endif
 #endif
 
 	IsUnderPostmaster = true;	/* we are a postmaster subprocess now */
@@ -1724,7 +1726,7 @@ PgstatCollectorMain(int argc, char *argv[])
 	 * Setup the descriptor set for select(2).	Since only one bit in the set
 	 * ever changes, we need not repeat FD_ZERO each time.
 	 */
-#ifndef HAVE_POLL
+#if !defined(HAVE_POLL) && !defined(WIN32)
 	FD_ZERO(&rfds);
 #endif
 
@@ -1771,8 +1773,10 @@ PgstatCollectorMain(int argc, char *argv[])
 		 * poll/select call, so this also limits speed of response to SIGQUIT,
 		 * which is more important.)
 		 *
-		 * We use poll(2) if available, otherwise select(2)
+		 * We use poll(2) if available, otherwise select(2).
+		 * Win32 has its own implementation.
 		 */
+#ifndef WIN32
 #ifdef HAVE_POLL
 		input_fd.fd = pgStatSock;
 		input_fd.events = POLLIN | POLLERR;
@@ -1810,6 +1814,10 @@ PgstatCollectorMain(int argc, char *argv[])
 
 		got_data = FD_ISSET(pgStatSock, &rfds);
 #endif   /* HAVE_POLL */
+#else /* WIN32 */
+		got_data = pgwin32_waitforsinglesocket(pgStatSock, FD_READ,
+											   PGSTAT_SELECT_TIMEOUT*1000);
+#endif
 
 		/*
 		 * If there is a message on the socket, read it and check for

src/include/port/win32.h

-/* $PostgreSQL: pgsql/src/include/port/win32.h,v 1.71 2007/01/25 21:50:49 momjian Exp $ */
+/* $PostgreSQL: pgsql/src/include/port/win32.h,v 1.72 2007/01/26 20:06:52 tgl Exp $ */
 
 #if defined(_MSC_VER) || defined(__BORLANDC__)
 #define WIN32_ONLY_COMPILER
@@ -289,7 +289,7 @@ int			pgwin32_recv(SOCKET s, char *buf, int len, int flags);
 int			pgwin32_send(SOCKET s, char *buf, int len, int flags);
 
 const char *pgwin32_socket_strerror(int err);
-int			pgwin32_waitforsinglesocket(SOCKET s, int what);
+int			pgwin32_waitforsinglesocket(SOCKET s, int what, int timeout);
 
 /* in backend/port/win32/security.c */
 extern int	pgwin32_is_admin(void);