diff -cpr pgsql-orig/src/backend/storage/buffer/bufmgr.c pgsql/src/backend/storage/buffer/bufmgr.c
*** pgsql-orig/src/backend/storage/buffer/bufmgr.c	2006-01-16 22:05:14.000000000 +0900
--- pgsql/src/backend/storage/buffer/bufmgr.c	2006-01-16 22:33:24.000000000 +0900
***************
*** 51,56 ****
--- 51,57 ----
  #include "utils/relcache.h"
  #include "utils/resowner.h"
  #include "pgstat.h"
+ #include "postmaster/bgwriter.h"
  
  
  /* Note: these two macros only work on shared buffers, not local ones! */
*************** static bool IsForInput;
*** 82,87 ****
--- 83,90 ----
  /* local state for LockBufferForCleanup */
  static volatile BufferDesc *PinCountWaitBuf = NULL;
  
+ /* interval to call AbsorbFsyncRequests in BufferSync */
+ #define BUFFERS_PER_ABSORB		10
  
  static bool PinBuffer(volatile BufferDesc *buf);
  static void PinBuffer_Locked(volatile BufferDesc *buf);
*************** BufferSync(void)
*** 892,897 ****
--- 895,902 ----
  {
  	int			buf_id;
  	int			num_to_scan;
+ 	int			absorb_counter;
+ 	int			absorb_interval = NBuffers / BUFFERS_PER_ABSORB;
  
  	/*
  	 * Find out where to start the circular scan.
*************** BufferSync(void)
*** 905,915 ****
--- 910,930 ----
  	 * Loop over all buffers.
  	 */
  	num_to_scan = NBuffers;
+ 	absorb_counter = 0;
  	while (num_to_scan-- > 0)
  	{
  		(void) SyncOneBuffer(buf_id, false);
  		if (++buf_id >= NBuffers)
  			buf_id = 0;
+ 		if (++absorb_counter >= absorb_interval)
+ 		{
+ 			/*
+ 			 * We absorb pending requests after each writing some
+ 			 * buffers to avoid overflow of the request queue.
+ 			 */
+ 			AbsorbFsyncRequests();
+ 			absorb_counter = 0;
+ 		}
  	}
  }
  
diff -cpr pgsql-orig/src/backend/storage/smgr/md.c pgsql/src/backend/storage/smgr/md.c
*** pgsql-orig/src/backend/storage/smgr/md.c	2006-01-16 22:05:14.000000000 +0900
--- pgsql/src/backend/storage/smgr/md.c	2006-01-16 22:17:46.000000000 +0900
*************** mdsync(void)
*** 728,733 ****
--- 728,739 ----
  			MdfdVec    *seg;
  
  			/*
+ 			 * We absorb pending requests at each fsync to avoid overflow of
+ 			 * the request queue.
+ 			 */
+ 			AbsorbFsyncRequests();
+ 
+ 			/*
  			 * Find or create an smgr hash entry for this relation. This may
  			 * seem a bit unclean -- md calling smgr?  But it's really the
  			 * best solution.  It ensures that the open file reference isn't