shared Locks

Hi group,

I have the following problem:

We have developed a ERP/PPS Developed with pgsql over the last 4 years.
Now we introduce it on some of our customers {pgsql works great and gets
good ratings :-)} and so we have to change Tablestructure and so on very
often. For technologie reasons every clients starts a Connection and
holds it until the client terminates his program.

So if we want to change a table structure (add a field or sth like this)
many clients own AccessShareLock's because it seams that a simple SELECT
* FROM table will grant a AccessShareLock and don't release it unitl the
connection is terminated. Is that true? Is it is possible to release
this lock without a disconnect? {Problem is that about 30 users has to
disconnect sometimes. :-( }

thnx for comments,
Daniel