Re: Issue with libpq < 8.4

On Tue, Aug 24, 2010 at 1:38 PM, Dave Page <dpage@pgadmin.org> wrote:
> On Tue, Aug 24, 2010 at 12:32 PM, Magnus Hagander <magnus@hagander.net>
> wrote:
>> On Tue, Aug 24, 2010 at 1:26 PM, Dave Page <dpage@pgadmin.org> wrote:
>>> On Tue, Aug 24, 2010 at 12:20 PM, Guillaume Lelarge
>>> <guillaume@lelarge.info> wrote:
>>>>
>>>> Can't we just have it set a variable we could check with a #ifdef? We
>>>> don't use PQconninfoParse in many files (actually, two). So it would be
>>>> pretty easy to add the #ifdef line, so that it won't be a big issue for
>>>> packagers.
>>>
>>> We use PQconninfoParse to check to ensure we have a new enough libpq
>>> to use application_name, so we can avoid sending it with older libpqs.
>>> If we disable the check for older libpqs, then we'll always get an
>>> error with them. The only way to fix that would be to only allow a 9.0
>>> libpq to be used.
>>>
>>> The current code at least allows 8.4 and 9.0 libpqs.
>>
>> What is it that we put into 8.4 that's making that one good enough? It
>> still didn't actually know about application_name, did it? Or did we
>> backpatch that knowledge, only not past 8.4?
>
> PQconninfoParse is in 8.4 and above. we use that to test at runtime
> whether or not we can use application_name.

Oh. Meh, we didn't have it at all before that. Forgot about that :S

So can't we do something like:

#ifdef HAVE_CONNINFO_PARSE
if (conninfoparse_shows_we_have_application_name_support)
   use connstr_with_appname;
else
   use connstr_without_appname;
#else
   use connstr_without_appname
#endif

? That way it should still work with older libpq, just not set
application_name...

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 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/