Now `FixedLenKeyIndex` just compressed common prefix, bytes in the middle of keys can also be compressed. For example: in mysql composite index with bigint columns, higher bytes of bigint may be all zeros, these bytes can be elminited.
Now
FixedLenKeyIndexjust compressed common prefix, bytes in the middle of keys can also be compressed.For example: in mysql composite index with bigint columns, higher bytes of bigint may be all zeros, these bytes can be elminited.