diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
new file mode 100644
index cd5ca4c..215f53c
*** a/src/backend/commands/vacuumlazy.c
--- b/src/backend/commands/vacuumlazy.c
***************
*** 97,102 ****
--- 97,104 ----
   */
  #define SKIP_PAGES_THRESHOLD	((BlockNumber) 32)
  
+ int JJFETCH=0;
+ 
  typedef struct LVRelStats
  {
  	/* hasindex = true means two-pass strategy; false means one-pass */
*************** count_nondeletable_pages(Relation onerel
*** 1581,1586 ****
--- 1583,1594 ----
  		 * keep the number of system calls and actual shared lock table
  		 * lookups to a minimum.
  		 */
+ 		if (JJFETCH && (blkno % JJFETCH) == 0 && blkno >=JJFETCH) 
+ 		{
+ 			int i;
+ 			for (i=-JJFETCH; i<0; i++)
+ 				PrefetchBuffer(onerel, MAIN_FORKNUM,blkno+i);
+ 		}
  		if ((blkno % 32) == 0)
  		{
  			instr_time	currenttime;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
new file mode 100644
index b8a0f9f..df25c47
*** a/src/backend/utils/misc/guc.c
--- b/src/backend/utils/misc/guc.c
*************** extern char *default_tablespace;
*** 111,116 ****
--- 111,117 ----
  extern char *temp_tablespaces;
  extern bool ignore_checksum_failure;
  extern bool synchronize_seqscans;
+ extern int	JJFETCH;
  
  #ifdef TRACE_SORT
  extern bool trace_sort;
*************** static struct config_bool ConfigureNames
*** 1637,1642 ****
--- 1638,1652 ----
  static struct config_int ConfigureNamesInt[] =
  {
  	{
+ 		{"JJFETCH", PGC_USERSET, DEVELOPER_OPTIONS,
+ 			gettext_noop("Do forward read prefetching during truncation"),
+ 			NULL,
+ 		},
+ 		&JJFETCH,
+ 		0, 0, INT_MAX,
+ 		NULL, NULL, NULL
+ 	},
+ 	{
  		{"archive_timeout", PGC_SIGHUP, WAL_ARCHIVING,
  			gettext_noop("Forces a switch to the next xlog file if a "
  						 "new file has not been started within N seconds."),