Re: modifying WaitEventSets (was: Performance degradation in commit ac1d794)

On Wed, May 4, 2016 at 3:54 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
>> On Wed, May 4, 2016 at 3:35 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>> Hmm ... wait, I take that back. poll() is required by SUS v2, which has
>>> been our minimum baseline spec for a long time (even my pet dinosaur HPUX
>>> has it). As long as we have an answer for Windows, it's hard to argue
>>> we can't require poll() elsewhere.
>
>> I don't think we'd necessarily need to completely de-support people
>> who still depend on select(). We'd just need to say, well,
>> WL_SOCKET_ERROR *may* report exceptional events on the socket, or it
>> may not, depending on how modern your platform is. In the use cases I
>> foresee, that would occasionally result in less-timely detection of
>> FDW connection loss, but nothing worse. I'm not prepared to get very
>> excited about that.
>
> I'm not either, but ...
>
>> But if we are confident that everything supports poll() and it's
>> always better than select(), another, possibly superior option is to
>> remove support for select() and see if anything breaks. If not, then
>> we only need to support three platform-specific implementations
>> instead of four, which I would find it difficult to complain about.
>
> ... the evidence available suggests that the select() code path has
> probably received zero buildfarm testing. Do we really want to ship
> a fourth implementation that we can't even vouch for?

I'm more than happy to rip it out, either now or after the tree opens
for 9.7 development.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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