All sales of property under execution must be made at auction, to the highest bidder. After sufficient property has been sold to satisfy the execution, no more can be sold. Neither the officer holding the execution nor his deputy can become a purchaser, or be interested in any purchase, at such sale. When the sale is of personal property, capable of manual delivery, it must be sold in such parcels as are likely to bring the highest price; and when the sale is of real property, consisting of several known lots or parcels, they must be sold separately, or when a portion of such real property is claimed by a third person, and he requires it to be sold separately, such portion must be thus sold. The judgment debtor, if present at the sale, may also direct the order in which property, real or personal, shall be sold, when such property consists of several known lots or parcels, or of articles which can be sold to advantage separately, and the sheriff must follow such directions.