Re: Use pread and pwrite instead of lseek + write and read

Oskari Saarenmaa <os(at)ohmu(dot)fi> writes:
> 17.08.2016, 22:11, Tom Lane kirjoitti:
>> I'd be more excited about this if the claimed improvement were more than
>> 1.5%, but you know as well as I do that that's barely above the noise
>> floor for most performance measurements. I'm left wondering why bother,
>> and why take any risk of de-optimizing on some platforms.

> I think it makes sense to try to optimize for the platforms that people
> actually use for performance critical workloads, especially if it also
> allows us to simplify the code and remove more lines than we add. It's
> nice if the software still works on legacy platforms, but I don't think
> we should be concerned about a hypothetical performance impact on
> platforms no one uses in production anymore.

Well, my point remains that I see little value in messing with
long-established code if you can't demonstrate a benefit that's clearly
above the noise level. We don't really know whether this change might
have adverse impacts somewhere --- either performance-wise or bug-wise ---
and for that amount of benefit I don't want to take the trouble to find
out.

regards, tom lane