Re: Overhauling GUCS

Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > The second idea is the idea of having one parameter depend on another. 
> > Not only could we do that for some of our existing parameters, but we
> > could have pseudo-parameters like concurrent_queries, memory_usage, and
> > extra_disk_space that could be at the top of postgresql.conf and then
> > affect the other settings.
> 
> We have tried to do that in the past, and it didn't work well *at all*.

We have?  When?

> The idea has a fundamental logical flaw, which is that it's not clear
> which parameter wins if the user changes both.

Yes, you could get into problems by having variable dependency loops,
but I see no way to easily improve configuration without it.

My idea was to have:
memory_usage = 128MB            ## pseudo-parametershared_buffers = $memory_usage * 0.75

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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