*** a/src/backend/utils/mmgr/aset.c
--- b/src/backend/utils/mmgr/aset.c
***************
*** 438,451 **** AllocSetContextCreate(MemoryContext parent,
  					  Size initBlockSize,
  					  Size maxBlockSize)
  {
! 	AllocSet	context;
  
  	/* Do the type-independent part of context creation */
! 	context = (AllocSet) MemoryContextCreate(T_AllocSetContext,
! 											 sizeof(AllocSetContext),
! 											 &AllocSetMethods,
! 											 parent,
! 											 name);
  
  	/*
  	 * Make sure alloc parameters are reasonable, and save them.
--- 438,454 ----
  					  Size initBlockSize,
  					  Size maxBlockSize)
  {
! 	AllocSet			set;
! 	MemoryContext		context;
  
  	/* Do the type-independent part of context creation */
! 	context = MemoryContextCreate(T_AllocSetContext,
! 								  sizeof(AllocSetContext),
! 								  &AllocSetMethods,
! 								  parent,
! 								  name);
! 
! 	set = (AllocSet) context;
  
  	/*
  	 * Make sure alloc parameters are reasonable, and save them.
***************
*** 459,467 **** AllocSetContextCreate(MemoryContext parent,
  	if (maxBlockSize < initBlockSize)
  		maxBlockSize = initBlockSize;
  	Assert(AllocHugeSizeIsValid(maxBlockSize)); /* must be safe to double */
! 	context->initBlockSize = initBlockSize;
! 	context->maxBlockSize = maxBlockSize;
! 	context->nextBlockSize = initBlockSize;
  
  	/*
  	 * Compute the allocation chunk size limit for this context.  It can't be
--- 462,470 ----
  	if (maxBlockSize < initBlockSize)
  		maxBlockSize = initBlockSize;
  	Assert(AllocHugeSizeIsValid(maxBlockSize)); /* must be safe to double */
! 	set->initBlockSize = initBlockSize;
! 	set->maxBlockSize = maxBlockSize;
! 	set->nextBlockSize = initBlockSize;
  
  	/*
  	 * Compute the allocation chunk size limit for this context.  It can't be
***************
*** 477,486 **** AllocSetContextCreate(MemoryContext parent,
  	 * and actually-allocated sizes of any chunk must be on the same side of
  	 * the limit, else we get confused about whether the chunk is "big".
  	 */
! 	context->allocChunkLimit = ALLOC_CHUNK_LIMIT;
! 	while ((Size) (context->allocChunkLimit + ALLOC_CHUNKHDRSZ) >
  		   (Size) ((maxBlockSize - ALLOC_BLOCKHDRSZ) / ALLOC_CHUNK_FRACTION))
! 		context->allocChunkLimit >>= 1;
  
  	/*
  	 * Grab always-allocated space, if requested
--- 480,489 ----
  	 * and actually-allocated sizes of any chunk must be on the same side of
  	 * the limit, else we get confused about whether the chunk is "big".
  	 */
! 	set->allocChunkLimit = ALLOC_CHUNK_LIMIT;
! 	while ((Size) (set->allocChunkLimit + ALLOC_CHUNKHDRSZ) >
  		   (Size) ((maxBlockSize - ALLOC_BLOCKHDRSZ) / ALLOC_CHUNK_FRACTION))
! 		set->allocChunkLimit >>= 1;
  
  	/*
  	 * Grab always-allocated space, if requested
***************
*** 500,519 **** AllocSetContextCreate(MemoryContext parent,
  					 errdetail("Failed while creating memory context \"%s\".",
  							   name)));
  		}
! 		block->aset = context;
  		block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ;
  		block->endptr = ((char *) block) + blksize;
! 		block->next = context->blocks;
! 		context->blocks = block;
  		/* Mark block as not to be released at reset time */
! 		context->keeper = block;
  
  		/* Mark unallocated space NOACCESS; leave the block header alone. */
  		VALGRIND_MAKE_MEM_NOACCESS(block->freeptr,
  								   blksize - ALLOC_BLOCKHDRSZ);
  	}
  
! 	return (MemoryContext) context;
  }
  
  /*
--- 503,522 ----
  					 errdetail("Failed while creating memory context \"%s\".",
  							   name)));
  		}
! 		block->aset = set;
  		block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ;
  		block->endptr = ((char *) block) + blksize;
! 		block->next = set->blocks;
! 		set->blocks = block;
  		/* Mark block as not to be released at reset time */
! 		set->keeper = block;
  
  		/* Mark unallocated space NOACCESS; leave the block header alone. */
  		VALGRIND_MAKE_MEM_NOACCESS(block->freeptr,
  								   blksize - ALLOC_BLOCKHDRSZ);
  	}
  
! 	return context;
  }
  
  /*