Is anyone working on this? Tom Lane wrote: > korry <[EMAIL PROTECTED]> writes: > > The problem is that, each time you go through > > pgwin32_waitforsinglesocket(), you tie the *same* kernel object > > (waitevent is static) to each socket. > > > The fix is pretty simple - just call WSAEventSelect( s, waitevent, 0 ) > > after WaitForMultipleObjectsEx() returns. That disassociates the socket > > from the Event (it will get re-associated the next time > > pgwin32_waitforsingleselect() is called. > > Hmm. Presumably we don't do this a whole lot (use multiple sockets) or > we'd have noticed before. Perhaps better would be to keep an additional > static variable saying which socket the event is currently associated > to, and only issue the extra WSAEventSelect calls if we need to change > it. Or is WSAEventSelect fast enough that it doesn't matter? >
Here's a simple patch that fixes the problem (I haven't explored the performance of this patch compared to Tom's suggestion).
-- Korry
Index: src/backend/port/win32/socket.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/port/win32/socket.c,v
retrieving revision 1.11
diff -w -c -r1.11 socket.c
*** src/backend/port/win32/socket.c 5 Mar 2006 15:58:35 -0000 1.11
--- src/backend/port/win32/socket.c 29 Jul 2006 12:13:19 -0000
***************
*** 132,137 ****
--- 132,154 ----
events[1] = waitevent;
r = WaitForMultipleObjectsEx(2, events, FALSE, INFINITE, TRUE);
+
+ /*
+ * NOTE: we must disassociate this socket from waitevent - if we don't, then
+ * we may accidentally fire waitevent at some point in the future if,
+ * for example, the socket is closed. That normally would not be a
+ * problem, but if you ever have two (or more) sockets in a single
+ * backend, they *ALL* share the same waitevent. So, if you pass through
+ * this function for socket1 and socket2, a close on EITHER socket will
+ * trigger an FD_CLOSE event, regardless of whether you're waiting for
+ * socket1 or socket2. That means that if you are waiting for socket1
+ * and socket2 gets some interesting traffic (an FD_CLOSE or FD_READ
+ * event for example), the above call to WaitForMultipleObjectsEx()
+ * will return even though nothing actually happened to socket1. Nasty...
+ */
+
+ WSAEventSelect(s, waitevent, 0 );
+
if (r == WAIT_OBJECT_0 || r == WAIT_IO_COMPLETION)
{
pgwin32_dispatch_queued_signals();
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