36 first bytes of a lob: meaning ?

Giganews Newsgroups
Subject: 36 first bytes of a lob: meaning ?
Posted by:  Spendius (spendi…@muchomail.com)
Date: 2 Sep 2006

I've noticed when you do a block dump that there are
36 extra bytes at the beginning of a lob field (and
the length of the lob returned by DBMS_LOB.GETLENGTH
substracts these 36 bytes from its result), even if it's
empty, so the length shown in a trace file is always
length of data + 36.
Someone knows what these byte are about ? Does it
depend on the block size ?