Re: [BUGS] BUG #1118: Misleading Commit message - Mailing list pgsql-hackers

While Alvarro, et al are messing with transaction syntax
this would be a good time to clarify this message.

--elein

On Fri, Jul 09, 2004 at 10:16:29AM -0400, Bruce Momjian wrote:
> 
> Do we want to add this to TODO:
> 
>     *  Issue an extra message when COMMIT completes a failed transaction
> 
> ---------------------------------------------------------------------------
> 
> elein wrote:
> > 
> > 
> > 
> > On Sun, Mar 28, 2004 at 10:23:26AM -0500, Tom Lane wrote:
> > > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > > > PostgreSQL Bugs List wrote:
> > > >> In a block transaction, whether or not there were errors in the transaction 
> > > >> issuing a commit; returns a COMMIT confirmation. 
> > > 
> > > > Uh, the tag indicates the COMMIT completed, not that it was a success.
> > > 
> > > The current philosophy on command tags is "the tag is the same as the
> > > command actually issued".  However we are talking about breaking that
> > > rule for EXECUTE, and if we do that, it's hard to say that we should
> > > continue to enforce the rule for COMMIT.  It would clearly be useful
> > > for a COMMIT that ends a failed transaction to report ROLLBACK instead.
> > > 
> > > > If we throw an error on a COMMIT, people willl think we did not close
> > > > the transacction,
> > > 
> > > ... which we wouldn't have.  That won't work.
> > > 
> > > > and if we return a ROLLBACK, they will think they issued a rollback.
> > > 
> > > Which, in effect, is what they did.  Is it likely that this would break
> > > any clients?  The intention of the current design rule is that clients
> > > can match the tag against the command they issued, but I don't know of
> > > any client code that actually does that.
> > > 
> > > In any case, we already have some inconsistencies:
> > > 
> > > regression=# begin;
> > > BEGIN
> > > regression=# end;
> > > COMMIT
> > > regression=# begin;
> > > BEGIN
> > > regression=# abort;
> > > ROLLBACK
> > > regression=#
> > > 
> > > so it seems that in some cases we're already following a rule more like
> > > "the tag is the same as the command actually *executed*".
> > > 
> > > I started out not wanting to make this change either, but the more
> > > I think about it the harder it is to hold that position.
> > > 
> > >             regards, tom lane
> > > 
> > > ---------------------------(end of broadcast)---------------------------
> > > TIP 3: if posting/reading through Usenet, please send an appropriate
> > >       subscribe-nomail command to majordomo@postgresql.org so that your
> > >       message can get through to the mailing list cleanly
> > 
> > The message could be something like:
> > COMMIT: Transaction rolled back due to errors
> > 
> > That way, it would reflect both the command and the action.
> > But I am concerned about the information rather than
> > the exact message if someone has better ideas.
> > 
> > My reason for submitting the bug was as Tom stated:
> > > It would clearly be useful
> > > for a COMMIT that ends a failed transaction to report ROLLBACK instead.
> > 
> > A commit that fails does not commit. It rolls back.  
> > 
> > In general, this would make it friendlier for new people and
> > space cadets that don't notice the last statement failed :-)
> > 
> > Elein
> > elein@varlena.com
> > 
> 
> -- 
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman@candle.pha.pa.us               |  (610) 359-1001
>   +  If your life is a hard drive,     |  13 Roberts Road
>   +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 2: you can get off all lists at once with the unregister command
>     (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)