Re: GUC for data checksums

On 2013-09-15 03:34:53 +0200, Bernd Helmle wrote:
>
>
> --On 15. September 2013 00:25:34 +0200 Andres Freund
> <andres(at)2ndquadrant(dot)com> wrote:
>
> >Looks like a good idea to me. The implementation looks sane as well,
> >except that I am not sure if we really need to introduce that faux
> >variable. If the variable cannot be set and we have a SHOW hook, do we
> >need it?
>
> It's along the line with the other informational variables like block_size
> et al. Do you want to have a function instead or what's your intention?

Well, you've added a "data_checksums" variable that won't ever get used,
right? You can't set the variable and the show hook doesn't actually use
it.
The reason you presumably did so is that there is no plain variable that
contains information about data checksums, we first need to read the
control file to know whether it's enabled and GUCs are initialized way
earlier than that.

A quick look unfortunately shows that there's no support for GUCs
without an actual underlying variable, so unless somebody adds that,
there doesn't seem to be much choice.

I think a comment documenting that the data_checksums variable is not
actually used would be appropriate.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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