Otherwise probe the next position , continuing until either the search key or an empty table is found. The number of elements to be put in the hash table should be estimated in advance and enough contiguous memory should be available. It relies on empty places in the table to help with the collision resolution. The table size for linear probing is greater than for separate chaining. The major drawback of linear probing is that, as the table becomes about half full, there is a tendency toward clustering .
Records start to appear in long strings of adjacent positions with gaps between strings.
Thus the sequential search needed to find an empty position becomes longer and longer. Linear probing uses less than five probes, on the average, for a hash table which is less than two-thirds full. As the table fills up the number of probes get very large.