Re: confusing checkpoint_flush_after / bgwriter_flush_after

On 11/25/2016 06:10 PM, Tom Lane wrote:
> Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> writes:
>>> #checkpoint_flush_after = 0 # 0 disables,
>>> # default is 256kB on linux, 0 otherwise
>
>>> I find this pretty confusing, because for all other GUCs in the file, the
>>> commented-out value is the default one. In this case that would mean "0",
>>> disabling the flushing.
>
>> Although I understand the issue, I'm not sure about -1 as a special value
>> to mean the default.
>
> Agreed --- I think that's making things more confusing not less.
>
> What we do in some similar cases is put the burden on initdb to fill in
> the correct value by modifying postgresql.conf.sample appropriately.
> It seems like that could be done easily here too. And it'd be a
> back-patchable fix.
>

I haven't realized initdb can do that. I agree that would be the best
solution.

--
Tomas Vondra http://www.2ndQuadrant.com
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