Establishment of an exclusive lock on each of an outer database ownership table and an inner database ownership table is attempted. In response to establishing the exclusive lock on each of the outer database ownership table and the inner database ownership table, a switch is made to a pair of overlapping shared locks on each of the outer database ownership table and the inner database ownership table. Release and re-acquisition of each of the pair of overlapping shared locks on the outer database ownership table and the inner database ownership table is alternated.