Re: Avoiding any locks in SQL Servers - read and understand....its magic.

Dieter Nöth <dnoeth_at_gmx.de> writes:

> Please point me to the PostgreSQL documentation where [MVCC] is
> descibed.

In the manual, in this section:

    <http://www.postgresql.org/docs/7.3/interactive/mvcc.html>

Locking is avoided by using MVCC, and reserving the option of failing a transaction (and raising an exception) if another transaction commits conflicting data during the attempted transaction. Thus, as Guido says, there are no locks, and nothing blocks anything -- but the application had better be prepared to retry a failed transaction.

Of course, explicit locking is available, so you can run transactions the normal way, and never notice MVCC except as good performance. :-)

-tih

-- 
Tom Ivar Helbekkmo, Senior System Administrator, EUnet Norway
www.eunet.no  T: +47-22092958 M: +47-93013940 F: +47-22092901