Re: Danger of automatic connection reset in psql

2016-11-22 13:02 GMT+01:00 Oleksandr Shulgin <oleksandr(dot)shulgin(at)zalando(dot)de>:

> On Tue, Nov 22, 2016 at 5:28 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> wrote:
>
>>
>> 2016-11-22 3:46 GMT+01:00 Robert Haas <robertmhaas(at)gmail(dot)com>:
>>
>>> On Mon, Nov 21, 2016 at 4:55 AM, Oleksandr Shulgin
>>> <oleksandr(dot)shulgin(at)zalando(dot)de> wrote:
>>> > On Tue, Nov 15, 2016 at 4:10 PM, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com>
>>> wrote:
>>> >>
>>> >> On 11/14/16 5:41 AM, Oleksandr Shulgin wrote:
>>> >>>
>>> >>> Automatic connection reset is a nice feature for server development,
>>> >>> IMO. Is it really useful for anything else is a good question.
>>> >>
>>> >>
>>> >> I use it all the time for application development; my rebuild script
>>> will
>>> >> forcibly kick everyone out to re-create the database. I put that in
>>> because
>>> >> I invariably end up with a random psql sitting somewhere that I don't
>>> want
>>> >> to track down.
>>> >>
>>> >> What currently stinks though is if the connection is dead and the next
>>> >> command I run is a \i, psql just dies instead of re-connecting. It'd
>>> be nice
>>> >> if before reading the script it checked connection status and
>>> attempted a
>>> >> reconnect.
>>> >>
>>> >>> At least an option to control that behavior seems like a good idea,
>>> >>> maybe even set it to 'no reconnect' by default, so that people who
>>> >>> really use it can make conscious choice about enabling it in their
>>> >>> .psqlrc or elsewhere.
>>> >>
>>> >>
>>> >> +1, I don't think it needs to be the default.
>>> >
>>> >
>>> > So if we go in this direction, should the option be specified from
>>> command
>>> > line or available via psqlrc (or both?) I think both make sense.
>>> >
>>> > What should be the option and control variable names? Something like:
>>> > --reconnect and RECONNECT? Should we allow reconnect in
>>> non-interactive
>>> > mode? I have no use case for that, but it might be different for
>>> others.
>>> > If non-interactive is not supported then it could be a simple boolean
>>> > variable, otherwise we might want something like a tri-state: on / off
>>> /
>>> > interactive (the last one being the default).
>>>
>>> I think it should just be another psql special variable, like
>>> AUTOCOMMIT or VERBOSITY. If the user wants to set it on the command
>>> line, they can just use -v. We don't need a separate, dedicated
>>> option for this, I think.
>>>
>>
> That makes sense to me.
>
> In this case depends on a default. For almost all scripts the sensible
>> value is "without reconnect". It be unfriendly to use this setting via -v
>> variable.
>>
>
> Well, if you're running a script it should not be affected as long as
> default value for this new variable is "interactive" or "off" (and you
> didn't override it in psqlrc). If you really want to get a "reconnect even
> from the script" type of behavior, then you'll have to use -v or set the
> variable from inside the script itself to "on".
>

ok

Pavel

>
> --
> Alex
>
>