Unchanging session id


#1

hello,
I have a serious problem that I cannot identify the reason. I am
logging every page access to my site to a table in my database to
track some data, alonside with session, user and client data. I am
seeing that same session id is given to numerous users even if their
host, user-agent access times etc. are completely different. I am
using session.session_id to track this data. and this session id
changes every day. 1 day session_id A is given to 16000 accesses
second day session_id B is given to 16000 accesses (other session ids
total upto atmost 50 accesses).

What can be the reason? what can be the thing that changes this
session id everyday? How can I override session_id generating function
(I couldnt find it)

Thanks in advance,
onur