*** guc.c.orig	Tue Mar 17 07:30:26 2009
--- guc.c	Tue Mar 17 07:47:10 2009
***************
*** 57,62 ****
--- 57,63 ----
  #include "postmaster/walwriter.h"
  #include "regex/regex.h"
  #include "storage/bufmgr.h"
+ #include "storage/lwlock.h"
  #include "storage/fd.h"
  #include "tcop/tcopprot.h"
  #include "tsearch/ts_cache.h"
***************
*** 167,172 ****
--- 168,174 ----
  static bool assign_maxconnections(int newval, bool doit, GucSource source);
  static bool assign_autovacuum_max_workers(int newval, bool doit, GucSource source);
  static bool assign_effective_io_concurrency(int newval, bool doit, GucSource source);
+ static bool assign_lock_wakeup_algorithm(int newval, bool doit, GucSource source);
  static const char *assign_pgstat_temp_directory(const char *newval, bool doit, GucSource source);
  
  static char *config_enum_get_options(struct config_enum *record, 
***************
*** 416,421 ****
--- 418,424 ----
  static int	wal_segment_size;
  static bool integer_datetimes;
  static int	effective_io_concurrency;
+ static int	lock_wakeup_algorithm;
  
  /* should be static, but commands/variable.c needs to get at these */
  char	   *role_string;
***************
*** 1727,1732 ****
--- 1730,1745 ----
  	},
  
  	{
+ 		{"lock_wakeup_algorithm", PGC_USERSET, RESOURCES,
+ 			gettext_noop("Select algorithm for lock waiters wakeup. 0 is default"),
+ 			gettext_noop("Select 1 for SMP systems, and higher for manual conrol of number of waiters to wake up.")
+ 		},
+ 		&lock_wakeup_algorithm,
+ 		0, 0, 32,
+ 		assign_lock_wakeup_algorithm, NULL
+ 	},
+ 
+ 	{
  		{"log_rotation_age", PGC_SIGHUP, LOGGING_WHERE,
  			gettext_noop("Automatic log file rotation will occur after N minutes."),
  			NULL,
***************
*** 7668,7673 ****
--- 7681,7698 ----
  #endif /* USE_PREFETCH */
  }
  
+ static bool
+ assign_lock_wakeup_algorithm(int newval, bool doit, GucSource source)
+ {
+ 	if ( newval < 0 && newval > 32)
+ 		return false;
+ 
+ 	if (doit)
+ 		LWLockWakeupAlgorithm= newval ;
+ 
+ 	return true;
+ }
+ 
  static const char *
  assign_pgstat_temp_directory(const char *newval, bool doit, GucSource source)
  {