[horde] datatree, sql vs null

[Hans Morten Kind]

We are running IMP as a webmail-service along with our general
imapservers, including horde_prefs, turba, kronolith and ingo supported by
apache and postgres served by redhat. The imap-backends runs solaris with
dovecot using zfs.  We have been running IMP since Jan-99 having app 7000
daily users peeking on 1200 concurrent users.

The webmail-server has been running with a load above 5 with several
postgres-processes claiming most cpu. Looking on output from
log_statements most sql-acesses were towards the tables of the the
datatree. When I switched from sql to null as the datatree driver in
horde/conf/conf.php, the load on the server sunk to under 0.5, the
postgres-processeses disapeared from 'top' and IMP responded better.

I can see no loss of functionality disabling the sql-driver of datatree.
Am I wrong?

Hans Morten Kind
IT-dep, Univ of Bergen