Horton

Re: proposal: schema variables

Hannu Krosing <hannu.krosing@2ndquadrant.com>

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From: Hannu Krosing <hannu.krosing@2ndquadrant.com>
To: Chris Travers <chris.travers@adjust.com>
Cc: Pavel Stehule <pavel.stehule@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2017-10-29T10:47:58Z
Lists: pgsql-hackers, pgsql-performance

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Move WAL sequence code into its own file

  2. Add ExplainState argument to pg_plan_query() and planner().

  3. Don't include access/htup_details.h in executor/tuptable.h

  4. Refactor to avoid code duplication in transformPLAssignStmt.

  5. Avoid including commands/dbcommands.h in so many places

  6. Restrict psql meta-commands in plain-text dumps.

  7. Split func.sgml into more manageable pieces

  8. Fix squashing algorithm for query texts

  9. EXPLAIN: Always use two fractional digits for row counts.

  10. Preliminary refactoring of plpgsql expression construction.

  11. plpgsql: pure parser and reentrant scanner

  12. Add some sanity checks in executor for query ID reporting

  13. Fix misleading error message context

  14. Add macros for looping through a List without a ListCell.

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.travers@adjust.com> wrote:

>
>
> On Sat, Oct 28, 2017 at 4:56 PM, Pavel Stehule <pavel.stehule@gmail.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>
>
>