Index: src/backend/storage/buffer/buf_table.c
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/backend/storage/buffer/buf_table.c,v
retrieving revision 1.50
diff -c -r1.50 buf_table.c
*** src/backend/storage/buffer/buf_table.c	1 Jan 2009 17:23:47 -0000	1.50
--- src/backend/storage/buffer/buf_table.c	17 May 2009 20:44:14 -0000
***************
*** 23,28 ****
--- 23,29 ----
  
  #include "storage/bufmgr.h"
  #include "storage/buf_internals.h"
+ #include "storage/lwlock.h"
  
  
  /* entry for buffer lookup hashtable */
***************
*** 60,66 ****
  	info.keysize = sizeof(BufferTag);
  	info.entrysize = sizeof(BufferLookupEnt);
  	info.hash = tag_hash;
! 	info.num_partitions = NUM_BUFFER_PARTITIONS;
  
  	SharedBufHash = ShmemInitHash("Shared Buffer Lookup Table",
  								  size, size,
--- 61,67 ----
  	info.keysize = sizeof(BufferTag);
  	info.entrysize = sizeof(BufferLookupEnt);
  	info.hash = tag_hash;
! 	info.num_partitions = NBufferPartitions;
  
  	SharedBufHash = ShmemInitHash("Shared Buffer Lookup Table",
  								  size, size,
Index: src/backend/storage/buffer/freelist.c
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/backend/storage/buffer/freelist.c,v
retrieving revision 1.66
diff -c -r1.66 freelist.c
*** src/backend/storage/buffer/freelist.c	1 Jan 2009 17:23:47 -0000	1.66
--- src/backend/storage/buffer/freelist.c	17 May 2009 20:39:29 -0000
***************
*** 284,290 ****
  	Size		size = 0;
  
  	/* size of lookup hash table ... see comment in StrategyInitialize */
! 	size = add_size(size, BufTableShmemSize(NBuffers + NUM_BUFFER_PARTITIONS));
  
  	/* size of the shared replacement strategy control block */
  	size = add_size(size, MAXALIGN(sizeof(BufferStrategyControl)));
--- 284,290 ----
  	Size		size = 0;
  
  	/* size of lookup hash table ... see comment in StrategyInitialize */
! 	size = add_size(size, BufTableShmemSize(NBuffers + NBufferPartitions));
  
  	/* size of the shared replacement strategy control block */
  	size = add_size(size, MAXALIGN(sizeof(BufferStrategyControl)));
***************
*** 312,320 ****
  	 * usage is of course NBuffers entries, but BufferAlloc() tries to insert
  	 * a new entry before deleting the old.  In principle this could be
  	 * happening in each partition concurrently, so we could need as many as
! 	 * NBuffers + NUM_BUFFER_PARTITIONS entries.
  	 */
! 	InitBufTable(NBuffers + NUM_BUFFER_PARTITIONS);
  
  	/*
  	 * Get or create the shared strategy control block
--- 312,320 ----
  	 * usage is of course NBuffers entries, but BufferAlloc() tries to insert
  	 * a new entry before deleting the old.  In principle this could be
  	 * happening in each partition concurrently, so we could need as many as
! 	 * NBuffers + NBufferPartitions entries.
  	 */
! 	InitBufTable(NBuffers + NBufferPartitions);
  
  	/*
  	 * Get or create the shared strategy control block
Index: src/backend/utils/init/globals.c
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/backend/utils/init/globals.c,v
retrieving revision 1.108
diff -c -r1.108 globals.c
*** src/backend/utils/init/globals.c	5 May 2009 19:59:00 -0000	1.108
--- src/backend/utils/init/globals.c	17 May 2009 20:49:07 -0000
***************
*** 104,109 ****
--- 104,110 ----
   * hook):
   */
  int			NBuffers = 1000;
+ int			NBufferPartitions = 16;
  int			MaxBackends = 100;
  int			MaxConnections = 90;
  
Index: src/backend/utils/misc/guc.c
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/backend/utils/misc/guc.c,v
retrieving revision 1.504
diff -c -r1.504 guc.c
*** src/backend/utils/misc/guc.c	3 May 2009 20:09:54 -0000	1.504
--- src/backend/utils/misc/guc.c	17 May 2009 21:36:21 -0000
***************
*** 58,63 ****
--- 58,64 ----
  #include "regex/regex.h"
  #include "storage/bufmgr.h"
  #include "storage/fd.h"
+ #include "storage/lwlock.h"
  #include "tcop/tcopprot.h"
  #include "tsearch/ts_cache.h"
  #include "utils/builtins.h"
***************
*** 165,170 ****
--- 166,172 ----
  static const char *show_tcp_keepalives_interval(void);
  static const char *show_tcp_keepalives_count(void);
  static bool assign_maxconnections(int newval, bool doit, GucSource source);
+ static bool assign_shared_buffer_partitions(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 const char *assign_pgstat_temp_directory(const char *newval, bool doit, GucSource source);
***************
*** 1361,1366 ****
--- 1363,1378 ----
  	},
  
  	{
+ 		{"shared_buffer_partitions", PGC_POSTMASTER, RESOURCES_MEM,
+ 			gettext_noop("Sets the number of shared buffer partitions used by the server."),
+ 			NULL,
+ 			GUC_NOT_IN_SAMPLE
+ 		},
+ 		&NBufferPartitions,
+ 		16, 16, MAX_NUM_BUFFER_PARTITIONS, assign_shared_buffer_partitions, NULL
+ 	},
+ 
+ 	{
  		{"temp_buffers", PGC_USERSET, RESOURCES_MEM,
  			gettext_noop("Sets the maximum number of temporary buffers used by each session."),
  			NULL,
***************
*** 7547,7552 ****
--- 7559,7586 ----
  }
  
  static bool
+ assign_shared_buffer_partitions(int newval, bool doit, GucSource source)
+ {
+ 	int b = 16;
+ 
+ 	for (;;)
+ 	{
+ 		if (b == newval)
+ 			break;
+ 
+ 		b *= 2;
+ 
+ 		if (b > newval || b > MAX_NUM_BUFFER_PARTITIONS)
+ 			return false;
+ 	}		
+ 
+ 	if (doit)
+ 		NBufferPartitions = newval;
+ 
+ 	return true;
+ }
+ 
+ static bool
  assign_autovacuum_max_workers(int newval, bool doit, GucSource source)
  {
  	if (newval + MaxConnections > INT_MAX / 4)
Index: src/include/storage/buf_internals.h
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/include/storage/buf_internals.h,v
retrieving revision 1.101
diff -c -r1.101 buf_internals.h
*** src/include/storage/buf_internals.h	12 Jan 2009 05:10:45 -0000	1.101
--- src/include/storage/buf_internals.h	17 May 2009 19:46:05 -0000
***************
*** 99,105 ****
   * NB: NUM_BUFFER_PARTITIONS must be a power of 2!
   */
  #define BufTableHashPartition(hashcode) \
! 	((hashcode) % NUM_BUFFER_PARTITIONS)
  #define BufMappingPartitionLock(hashcode) \
  	((LWLockId) (FirstBufMappingLock + BufTableHashPartition(hashcode)))
  
--- 99,105 ----
   * NB: NUM_BUFFER_PARTITIONS must be a power of 2!
   */
  #define BufTableHashPartition(hashcode) \
! 	((hashcode) % NBufferPartitions)
  #define BufMappingPartitionLock(hashcode) \
  	((LWLockId) (FirstBufMappingLock + BufTableHashPartition(hashcode)))
  
Index: src/include/storage/lwlock.h
===================================================================
RCS file: /home/sriggs/pg/REPOSITORY/pgsql/src/include/storage/lwlock.h,v
retrieving revision 1.42
diff -c -r1.42 lwlock.h
*** src/include/storage/lwlock.h	3 Mar 2009 08:11:24 -0000	1.42
--- src/include/storage/lwlock.h	17 May 2009 20:19:19 -0000
***************
*** 21,30 ****
   */
  
  /* Number of partitions of the shared buffer mapping hashtable */
! #define NUM_BUFFER_PARTITIONS  16
  
  /* Number of partitions the shared lock tables are divided into */
! #define LOG2_NUM_LOCK_PARTITIONS  4
  #define NUM_LOCK_PARTITIONS  (1 << LOG2_NUM_LOCK_PARTITIONS)
  
  /*
--- 21,32 ----
   */
  
  /* Number of partitions of the shared buffer mapping hashtable */
! #define MAX_NUM_BUFFER_PARTITIONS  256
! 
! extern PGDLLIMPORT int NBufferPartitions;
  
  /* Number of partitions the shared lock tables are divided into */
! #define LOG2_NUM_LOCK_PARTITIONS 4
  #define NUM_LOCK_PARTITIONS  (1 << LOG2_NUM_LOCK_PARTITIONS)
  
  /*
***************
*** 69,75 ****
  	SyncScanLock,
  	/* Individual lock IDs end here */
  	FirstBufMappingLock,
! 	FirstLockMgrLock = FirstBufMappingLock + NUM_BUFFER_PARTITIONS,
  
  	/* must be last except for MaxDynamicLWLock: */
  	NumFixedLWLocks = FirstLockMgrLock + NUM_LOCK_PARTITIONS,
--- 71,77 ----
  	SyncScanLock,
  	/* Individual lock IDs end here */
  	FirstBufMappingLock,
! 	FirstLockMgrLock = FirstBufMappingLock + MAX_NUM_BUFFER_PARTITIONS,
  
  	/* must be last except for MaxDynamicLWLock: */
  	NumFixedLWLocks = FirstLockMgrLock + NUM_LOCK_PARTITIONS,