*** pltcl.c.orig	2007-09-10 12:58:34.000000000 -0400
--- pltcl.c	2007-09-11 11:37:33.363222114 -0400
***************
*** 163,168 ****
--- 163,258 ----
  static void pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc,
  						   Tcl_DString *retval);
  
+ /**********************************************************************
+  *  Declarations for functions overriden using Tcl_SetNotifier. 
+  **********************************************************************/
+ static int fakeThreadKey;   /* To give valid address for ClientData */
+ 
+ static ClientData
+ pltcl_InitNotifier _ANSI_ARGS_((void));
+ 
+ static void
+ pltcl_FinalizeNotifier _ANSI_ARGS_((ClientData clientData));
+ 
+ static void
+ pltcl_SetTimer _ANSI_ARGS_((Tcl_Time *timePtr));
+ 
+ static void
+ pltcl_AlertNotifier _ANSI_ARGS_((ClientData clientData));
+ 
+ static void
+ pltcl_CreateFileHandler _ANSI_ARGS_((int fd, int mask, Tcl_FileProc *proc, ClientData clientData));
+ 
+ static void
+ pltcl_DeleteFileHandler _ANSI_ARGS_((int fd));
+ 
+ static void
+ pltcl_ServiceModeHook _ANSI_ARGS_((int mode));
+ 
+ static int
+ pltcl_WaitForEvent _ANSI_ARGS_((Tcl_Time *timePtr));
+ 
+ /**********************************************************************
+  *  Definitions for functions overriden using Tcl_SetNotifier. 
+  *  These implementations effectively disable the TCL Notifier subsystem.
+  *  This is okay because we never enter the TCL event loop from postgres,
+  *  so the notifier capabilities are initialized, but never used.
+  *  
+  *  NOTE: Only InitNotifier and DeleteFileHandler ever seem to get called
+  *        by postgres, but we implement all the functions for completeness.
+  **********************************************************************/
+ 
+ ClientData
+ pltcl_InitNotifier() 
+ {
+     return (ClientData) &(fakeThreadKey); 
+ }
+ 
+ void
+ pltcl_FinalizeNotifier(clientData)
+     ClientData clientData;      /* Not used. */
+ {
+ }
+ 
+ void
+ pltcl_SetTimer(timePtr)
+     Tcl_Time *timePtr;
+ {
+ }
+ 
+ void
+ pltcl_AlertNotifier(clientData)
+     ClientData clientData;
+ {
+ }
+ 
+ void
+ pltcl_CreateFileHandler(fd, mask, proc, clientData)
+     int fd;      
+     int mask;   
+     Tcl_FileProc *proc; 
+     ClientData clientData;
+ {
+ }
+ 
+ void
+ pltcl_DeleteFileHandler(fd)
+     int fd;  
+ {
+ }
+ 
+ void
+ pltcl_ServiceModeHook(mode)
+     int mode; 
+ {
+ }
+ 
+ int
+ pltcl_WaitForEvent(timePtr)
+     Tcl_Time *timePtr;      /* Maximum block time, or NULL. */
+ {
+     return 0;
+ }
  
  /*
   * This routine is a crock, and so is everyplace that calls it.  The problem
***************
*** 189,194 ****
--- 279,287 ----
  void
  _PG_init(void)
  {
+     /*  Notifier structure used to override functions in Notifier subsystem*/
+     Tcl_NotifierProcs notifier;
+ 
  	/* Be sure we do initialization only once (should be redundant now) */
  	if (pltcl_pm_init_done)
  		return;
***************
*** 199,204 ****
--- 292,316 ----
  #endif
  
  	/************************************************************
+      * Override the functions in the Notifier subsystem.
+      *
+      * We do this to prevent the postgres backend from becoming 
+      * multithreaded, which happens in the default version of 
+      * Tcl_InitNotifier if the TCL library has been compiled with 
+      * multithreading support (i.e. when TCL_THREADS is defined 
+      * under Unix, and in all cases under Windows). 
+ 	 ************************************************************/
+     notifier.setTimerProc          = pltcl_SetTimer; 
+     notifier.waitForEventProc      = pltcl_WaitForEvent;
+     notifier.createFileHandlerProc = pltcl_CreateFileHandler; 
+     notifier.deleteFileHandlerProc = pltcl_DeleteFileHandler;
+     notifier.initNotifierProc      = pltcl_InitNotifier;
+     notifier.finalizeNotifierProc  = pltcl_FinalizeNotifier;
+     notifier.alertNotifierProc     = pltcl_AlertNotifier; 
+     notifier.serviceModeHookProc   = pltcl_ServiceModeHook; 
+     Tcl_SetNotifier(&notifier); 
+ 
+ 	/************************************************************
  	 * Create the dummy hold interpreter to prevent close of
  	 * stdout and stderr on DeleteInterp
  	 ************************************************************/