On Thu, Jan 21, 2010 at 1:12 PM, John Mitchell <mitchelljj98@gmail.com> wrote: > Hi, > > In reading the documentation it states that the SQL dump backup does not > block other operations on the database while it is working.
yes, pg_dump opens serializable transaction thus guarantees data to be the exact snapshot (as opposed to the default isolation level, which is called 'read commited' not without reason).
> > I presume that while a restore is occurring that no reads or updates are > allowed against the restored database.
nope, what restoring does, is just running all the commands in the pg_dump (whether it is binary or textual). So as soon as the database is created, it is treated just as any connection, thus allows you to connect and use it.
> What locking mechanism is used for Master-Slave Replication?
master slave that's introduced in what's to be 9.0 (aka 8.5), uses WAL shipping. So it doesn't require any extra locking.
