Re: Fairly serious bug induced by latest guc enum changes

Tom Lane wrote:
> Magnus Hagander <magnus@hagander.net> writes:
>> Not having looked at md.c (I confess...) but don't we have a problem in
>> case we have closed the file without fsyncing it, and then change the
>> fsync parameter?
> 
> Well, we don't promise to retroactively fsync stuff we didn't before;
> and I wouldn't expect that to happen if I were changing the setting.
> What I *would* expect is that the system immediately starts to act
> according to the new setting, and that's not true as the code stands.
> 
> As you say, the whole thing is pretty dubious from a data safety
> standpoint anyway.  What I am concerned about here is people trying to
> compare performance measurements under different settings, and not being
> aware that the system's behavior doesn't change when they tell it to.

Well, if they're running a performance measure that generates <16Mb
data, I don't think they'll get very usable numbers anyway...

//Magnus