When a new key is inserted, and one of its two cells is empty, it may be placed in that cell. However, when both cells are already full, it will be necessary to move other keys to their second locations (or back to their first locations) to make room for the new key. A greedy algorithm is used: The new key is inserted in one of its two possible locations, "kicking out", that is, displacing, any key that might already reside in this location. This displaced key is then inserted in its alternative location, again kicking out any key that might reside there. The process continues in the same way until an empty position is found, completing the algorithm. However, it is possible for this insertion process to fail, by entering an infinite loop or by finding a very long chain (longer than a preset threshold that is logarithmic in the table size). In this case, the hash table is rebuilt in-place using new hash functions: