*** a/src/backend/utils/hash/dynahash.c
--- b/src/backend/utils/hash/dynahash.c
***************
*** 1022,1027 **** hash_update_hash_key(HTAB *hashp,
--- 1022,1028 ----
  	uint32		newhashvalue;
  	Size		keysize;
  	uint32		bucket;
+ 	uint32		newbucket;
  	long		segment_num;
  	long		segment_ndx;
  	HASHSEGMENT segp;
***************
*** 1078,1087 **** hash_update_hash_key(HTAB *hashp,
  	 */
  	newhashvalue = hashp->hash(newKeyPtr, hashp->keysize);
  
! 	bucket = calc_bucket(hctl, newhashvalue);
! 
! 	segment_num = bucket >> hashp->sshift;
! 	segment_ndx = MOD(bucket, hashp->ssize);
  
  	segp = hashp->dir[segment_num];
  
--- 1079,1087 ----
  	 */
  	newhashvalue = hashp->hash(newKeyPtr, hashp->keysize);
  
! 	newbucket = calc_bucket(hctl, newhashvalue);
! 	segment_num = newbucket >> hashp->sshift;
! 	segment_ndx = MOD(newbucket, hashp->ssize);
  
  	segp = hashp->dir[segment_num];
  
***************
*** 1115,1126 **** hash_update_hash_key(HTAB *hashp,
  
  	currBucket = existingElement;
  
! 	/* OK to remove record from old hash bucket's chain. */
! 	*oldPrevPtr = currBucket->link;
  
! 	/* link into new hashbucket chain */
! 	*prevBucketPtr = currBucket;
! 	currBucket->link = NULL;
  
  	/* copy new key into record */
  	currBucket->hashvalue = newhashvalue;
--- 1115,1129 ----
  
  	currBucket = existingElement;
  
! 	if (bucket != newbucket)
! 	{
! 		/* OK to remove record from old hash bucket's chain. */
! 		*oldPrevPtr = currBucket->link;
  
! 		/* link into new hashbucket chain */
! 		*prevBucketPtr = currBucket;
! 		currBucket->link = NULL;
! 	}
  
  	/* copy new key into record */
  	currBucket->hashvalue = newhashvalue;