When a key is defined with compression of leading characters, all leading characters that match leading characters in the preceding key are not stored in the index file. However, information is stored to enable the key to be correctly reconstructed.
For example, assume that records are written with the following key values in a key defined with compression of leading characters:
AXYZBBB BBCDEFG BBCXYZA BBCXYEF BEFGHIJ CABCDEF
The keys actually stored in the index file are:
AXYZBBB BBCDEFG XYZA EF EFGHIJ CABCDEF