[pgpool-hackers: 130] Re: Enabling -D switch of pgpool by default

Gurjeet Singh singh.gurjeet at gmail.com
Thu Sep 13 07:23:52 JST 2012


On Wed, Sep 12, 2012 at 6:16 PM, alex <alex at smalldemons.com> wrote:

>  On 9/12/12 3:06 PM, Gurjeet Singh wrote:
>
>  On Wed, Sep 12, 2012 at 5:45 PM, Tatsuo Ishii <ishii at postgresql.org>wrote:
>
>> > So far I haven't heard of any damaging or detrimental effects of -D
>> option.
>> > The only effect and overhead that I can verify is that with -D option
>> > pgpool will connect to every backend_hostname to verify whether the
>> > database backend is reachable. This may cause some slowdown in initial
>> > pgpool startup, but the upside is that the backend_status value reflects
>> > the true status of a backend.
>>
>>  Really? At least Alex and I are not sure if it's a really good idea,
>> while no one is with your idea. Also I would like to hear from Devrim
>> since he is the mainter of init scripts.
>>
>
> Well, the only argument I have heard is that once added to init script, it
> will be difficult to disable its effect, like one could do by using $OPTS
> env variable. What I consider 'damaging or detrimental' is if someone said
> "That'll cause wrong results in certain mode of operation (say
> replication)" or "this will cause a crash" or "this will make some backend
> nodes unavailable via pgpool". If -D option does not cause any unintended
> effects, I think it is safe for me to use. I hope you get my point.
>
>
> Safe for you to use doesn't justify changing the default behavior,
> though.  It just makes it safe for you to use.
>
> Consider the scenario in which someone disables a backend intentionally to
> do some kind of work on it.  In that case the user would want the backend
> to remain disabled until the work is done and he/she manually re-enables
> the backend.  The current default acts that way and users would reasonably
> expect v3.3 and above to keep the same default behavior.
>

This is the kind of argument I was looking for. This makes me reconsider
this now.


>
> Again, /etc/sysconfig/pgpool allows you to do whatever you want --and
> shouldn't get overwritten by rpm updates or the spec file needs fixing--
> without changing expected behavior for everyone else.
>



-- 
Gurjeet Singh

http://gurjeet.singh.im/
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