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Home -> Community -> Usenet -> c.d.o.server -> 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: +47-22092901Received on Tue Aug 19 2003 - 05:04:11 CDT