AW: AW: Issue NOTICE for attempt to raise lock level?

> >> I am working on eliminating the "relation NNN modified while in use"
> >> misfeature by instead grabbing a lock on each relation at first use
> >> in a statement, and holding that lock till end of transaction. 
> 
> > As anticipated, I object :-) 
> 
> Your objection is founded on two misunderstandings.  In the first place,
> we are *always* inside a transaction when executing a query. It may be
> an implicit one-statement transaction, but it's still a transaction.

Ok, but I thought there was some optimization for readonly statements.

> In the second place, we already grab locks that we do not release till
> end of xact for all user-level queries.  The problem is that we grab
> them too late, ie, in the executor.  I'm just planning to move up the
> grab till first use.

For a "select  colname from tablename" we do not currently hold any lock 
until end of tx. This is the situation you described, and I am worried about.

Andreas