Re: Proposal for Allow postgresql.conf values to be changed via SQL

Amit Kapila <amit(dot)kapila(at)huawei(dot)com> writes:
> We have discussion about below 3 different syntaxes for this command
>
> 1. ALTER SYSTEM
> 2. SET PERSISENT
> 3. pg_change_conf()
>
> I think to conclude, we need to evaluate which syntax has more advantages.
> Comparison for above syntax

I think ALTER SYSTEM should be what Peter Eisentraut proposed in another
thread, using system catalogs and thus not supporting the whole range of
parameters and reset behavior on SIGHUP. That's still very useful, and
seems to me clear enough to document.

Then, I think you could implement a SET PERSISENT command that call the
pg_change_conf() fonction. The problem is that you then can't have the
command unavailable in a transaction block if all it does is calling the
function, because the function call needs to happen in a transaction.

I'd vote for having a lock that serialize any calls to that function. My
understanding of the use cases makes it really ok not be to accept any
concurrency behavior here.

Regards,
--
Dimitri Fontaine
http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support