Re: proposal: schema variables

but you can always do

with a (id, value) as (
values (1, 'foo'), (2, 'bar'), (3, 'baz')
)
select set_config('custom.value',(select value from a where id = 2),true);

if you are worried about the evaluation order

On 29 October 2017 at 09:51, Chris Travers <chris(dot)travers(at)adjust(dot)com> wrote:

>
>
> On Sat, Oct 28, 2017 at 4:56 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> wrote:
>
>>
>>>
>> The creating database objects and necessary infrastructure is the most
>> simple task of this project. I'll be more happy if there are zero
>> intersection because variables and GUC are designed for different purposes.
>> But due SET keyword the intersection there is.
>>
>> When I thinking about it, I have only one, but important reason, why I
>> prefer design new type of database object -the GUC are stack based with
>> different default granularity - global, database, user, session, function.
>> This can be unwanted behave for variables - it can be source of hard to
>> detected bugs. I afraid so this behave can be too messy for usage as
>> variables.
>>
>> @1 I have not clean opinion about it - not sure if rights are good enough
>> - probably some user limits can be more practical - but can be hard to
>> choose result when some user limits and GUC will be against
>>
>
> I was mostly thinking that users can probably set things like work_mem and
> possibly this might be a problem.
>
>
>> @2 With variables typed custom GUC are not necessary
>>
>
> I don't know about that. For example with the geoip2lookup extension it
> is nice that you could set the preferred language for translation on a per
> user basis or the mmdb path on a per-db basis.
>
>
>> @3 Why you need it? It is possible with set_config function now.
>>
>
> Yeah you could do it safely with set_config and a CTE, but suppose I have:
>
> with a (Id, value) as (values (1::Int, 'foo'), (2, 'bar'), (3, 'baz'))
> SELECT set_config('custom_val', value) from a where id = 2;
>
> What is the result out of this? I would *expect* that this would probably
> run set_config 3 times and filter the output.
>
>
>>
>> Regards
>>
>> Pavel
>>
>>
>>
>>
>>>
>>>
>>>> regards
>>>>
>>>> Pavel
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Best Regards,
>>> Chris Travers
>>> Database Administrator
>>>
>>> Tel: +49 162 9037 210 <+49%20162%209037210> | Skype: einhverfr |
>>> www.adjust.com
>>> Saarbrücker Straße 37a, 10405 Berlin
>>> <https://maps.google.com/?q=Saarbr%C3%BCcker+Stra%C3%9Fe+37a,+10405+Berlin&entry=gmail&source=g>
>>>
>>>
>>
>
>
> --
> Best Regards,
> Chris Travers
> Database Administrator
>
> Tel: +49 162 9037 210 <+49%20162%209037210> | Skype: einhverfr |
> www.adjust.com
> Saarbrücker Straße 37a, 10405 Berlin
> <https://maps.google.com/?q=Saarbr%C3%BCcker+Stra%C3%9Fe+37a,+10405+Berlin&entry=gmail&source=g>
>
>