Re: handling unconvertible error messages - Mailing list pgsql-hackers

From Kyotaro HORIGUCHI
Subject Re: handling unconvertible error messages
Date
Msg-id 20160808.171821.100221089.horiguchi.kyotaro@lab.ntt.co.jp
Whole thread Raw
In response to Re: handling unconvertible error messages  (Victor Wagner <vitus@wagner.pp.ru>)
Responses Re: handling unconvertible error messages  (Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>)
Re: handling unconvertible error messages  (Victor Wagner <vitus@wagner.pp.ru>)
List pgsql-hackers
At Mon, 8 Aug 2016 10:19:10 +0300, Victor Wagner <vitus@wagner.pp.ru> wrote in
<20160808101910.49beeed6@fafnir.local.vm>
> On Fri, 5 Aug 2016 11:21:44 -0400
> Peter Eisentraut <peter.eisentraut@2ndquadrant.com> wrote:
> 
> > On 8/4/16 2:45 AM, Victor Wagner wrote:
> > > 4. At the session startup try to reinitializie LC_MESSAGES locale
> > > category with the combination
> > > of the server (or better client-send) language and region and
> > > client-supplied encoding, and if this failed, use untranslated error
> > > message. Obvoisly, attempt to set locale to ru_RU.ISO8859-1 would
> > > fail. so, if client would ask server with ru_RU.UTF-8 default
> > > locale to use LATIN1 encoding, server would fallback to
> > > untranslated messages.  
> 
> > I think this is basically my solution (1), with the same problems.
> 
> I think, that there is a big difference from server point of view.
> 
> You propose that both translated and untranslated message should be
> passed around inside backend. It has some benefits, but requires
> considerable reworking of server internals.

Agreed.

> My solution doesn't require keeping both original message and
> translated one during all call stack unwinding. It just checks if
> combination of language and encoding is supported by the NLS subsystem,
> and if not, falls back to untranslated message  for entire session.

Looking at check_client_encoding(), the comment says as following.

| * If we are not within a transaction then PrepareClientEncoding will not
| * be able to look up the necessary conversion procs.  If we are still
| * starting up, it will return "OK" anyway, and InitializeClientEncoding
| * will fix things once initialization is far enough along.  After

We shold overcome this to realize startup-time check for
conversion procs.

> It is much more local change and is comparable by complexity with one,
> proposed by Tom Lane.

I'm not sure what messages may be raised before authentication
but it can be a more generic-solution. (Adding check during
on-session.)

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center





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