*** ./src/backend/utils/mmgr/aset.c.orig	Mon May  9 17:55:36 2005
--- ./src/backend/utils/mmgr/aset.c	Wed May 11 15:38:33 2005
***************
*** 123,128 ****
--- 123,135 ----
  
  /*
   * AllocSetContext is our standard implementation of MemoryContext.
+  *
+  *		shouldReset shows whether AllocSetReset should work. This is
+  *		used to reduce cycle of AllocSetReset. When new block is
+  *		allocated or freed chunk is put on freelist, it will be set
+  *		to true. If it is false, AllocSetReset have nothing to do.
+  *		In this way, the context reset repeatedly after a small allocation
+  *		such as per-tuple contexts can be reset fast. 
   */
  typedef struct AllocSetContext
  {
***************
*** 135,140 ****
--- 142,148 ----
  	Size		maxBlockSize;	/* maximum block size */
  	AllocBlock	keeper;			/* if not NULL, keep this block over
  								 * resets */
+ 	bool		shouldReset;	/* should AllocSetReset work? */
  } AllocSetContext;
  
  typedef AllocSetContext *AllocSet;
***************
*** 395,400 ****
--- 403,416 ----
  	AllocSetCheck(context);
  #endif
  
+ 	/*
+ 	 * Shortcut. See comment at the definition of AllocSetContext.
+ 	 */
+ 	if(!set->shouldReset)
+ 		return;
+ 
+ 	set->shouldReset = false;
+ 
  	/* Clear chunk freelists */
  	MemSet(set->freelist, 0, sizeof(set->freelist));
  	/* New blocks list is either empty or just the keeper block */
***************
*** 454,459 ****
--- 470,476 ----
  	MemSet(set->freelist, 0, sizeof(set->freelist));
  	set->blocks = NULL;
  	set->keeper = NULL;
+ 	set->shouldReset = false;
  
  	while (block != NULL)
  	{
***************
*** 531,536 ****
--- 548,554 ----
  			block->next = NULL;
  			set->blocks = block;
  		}
+ 		set->shouldReset = true;
  
  		AllocAllocInfo(set, chunk);
  		return AllocChunkGetPointer(chunk);
***************
*** 723,728 ****
--- 741,747 ----
  
  		block->next = set->blocks;
  		set->blocks = block;
+ 		set->shouldReset = true;
  	}
  
  	/*
***************
*** 816,821 ****
--- 835,841 ----
  		chunk->requested_size = 0;
  #endif
  		set->freelist[fidx] = chunk;
+ 		set->shouldReset = true;
  	}
  }