[Pgpool-hackers] removing backend_socket_dir parameter ?

[Guillaume Lelarge]

Le 06/01/2011 15:43, Jehan-Guillaume (ioguix) de Rorthais a écrit :
> Le 05/01/2011 10:51, Jehan-Guillaume (ioguix) de Rorthais a écrit :
>> Le 05/01/2011 10:22, Tatsuo Ishii a écrit :
>>>> Le 04/01/2011 15:38, Jehan-Guillaume (ioguix) de Rorthais a écrit :
>>>>> Le 04/01/2011 15:13, Guillaume Lelarge a écrit :
>>>>>> Hi,
>>>>>
>>>>>> Le 04/01/2011 14:27, Jehan-Guillaume (ioguix) de Rorthais a écrit :
>>>>>>> [...]
>>>>>>> pgPool is currently using the parameter "backend_socket_dir" to define where it
>>>>>>> can find the backend unix socket files.
>>>>>>>
>>>>>>> However, from the libpq world, we just use one parameter for both unix or inet
>>>>>>> socket: host. If this parameter starts with '/', then this is a unix socket. All
>>>>>>> other values are inet connections. See:
>>>>>>>
>>>>>>> http://www.postgresql.org/docs/9.0/static/libpq-connect.html#LIBPQ-CONNECT-HOST
>>>>>>>
>>>>>>> Back in pgPool world, the equivalent parameter is "backend_hostnameN". So, when
>>>>>>> I was setting up a dev environment yesterday, I naturally set this parameter  to
>>>>>>> my unix path (I'm using Debian) and end up with a hostname resolution error.
>>>>>>>
>>>>>>> So you'll find in attachment a patch to remove the "backend_socket_dir"
>>>>>>> parameter and use the libpq policy. Moreover, on empty "backend_hostnameN"
>>>>>>> value, the patch fall back to DEFAULT_SOCKET_DIR.
>>>>>>>
>>>>>
>>>>>> This patch is really interesting. This is something I had on my todo
>>>>>> list for quite some time.
>>>>>
>>>>> Glad to hear that :)
>>>>> I wasn't the only one wondering about this then :)
>>>>>
>>>>>>> I realize it will break compatibility with older configuration file. But in a
>>>>>>> first step, I prefer something clean and start discussing this issue with you if
>>>>>>> you really mind this.
>>>>>>>
>>>>>
>>>>>> On the configuration file, compatibility of configuration file is never
>>>>>> garantied. So I don't think this is such an issue. We need to make it
>>>>>> clear that the parameter has a new mail.
>>>>>
>>>>> s/new mail/new name/
>>>>>
>>>>> well, it's not a new name, we just drop one and promote an existing one to deal
>>>>> with both unix and inet socket :)
>>>>>
>>>>>> If we really want to maintain the compatibility on this issue, we could
>>>>>> still support the old parameter during two or three major releases. I
>>>>>> guess we need to put a warning in the log to say "hey guy, you're still
>>>>>> using that old obsolete configuration parameter, you should better
>>>>>> change with this one".
>>>>>
>>>>> Yeah. What I have in mind is :
>>>>>   if backend_hostnameN == ''
>>>>>     if not backend_socket_dir
>>>>>       backend_hostnameN = DEFAULT_SOCKET_DIR
>>>>>     else
>>>>>       log « please stop using that »
>>>>>       backend_hostnameN = backend_socket_dir
>>>>>
>>>>> But really, I would prefer to drop backend_socket_dir and keep the code clean.
>>>>>
>>>>
>>>> You can't have it both ways. Either you please your users, or you please
>>>> your developpers. I think we should do the former.
> 
>>> Agreed. I learned it in a hard way:-)
> 
>>> Now I think the idea is great and am looking forward to accepting for
>>> the next release.
> 
>> Thank you !
> 
> So here is the new patch including backward compatibility with backend_socket_dir.
> 

Seems good to me. Could you also get rid of backend_socket_dir in the
sample configuration files? this parameter won't be the prefered way to
set the socket, so it shouldn't be in the sample conf files.

Thanks.


-- 
Guillaume
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