Re: Sync Rep v19

On Sun, Mar 6, 2011 at 2:59 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Sat, Mar 5, 2011 at 11:56 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>>> Even though postmaster dies, the waiting backend keeps waiting until
>>> the timeout expires. Instead, the backends should periodically check
>>> whether postmaster is alive, and then they should exit immediately
>>> if it's not alive, as well as other process does? If the timeout is
>>> disabled, such backends would get stuck infinitely.
>>
>> Will wake them every 60 seconds
>
> I don't really see why sync rep should be responsible for solving this
> problem, which is an issue in many other situations as well, only for
> itself. In fact I think I'd prefer that it didn't, and that we wait
> for a more general solution that will actually fix this problem for
> real.

I agree if such a general solution will be committed together with sync rep.
Otherwise, because of sync rep, the backend can easily get stuck *infinitely*.
When postmaster is not alive, all the existing walsenders exit immediately
and no new walsender can appear. So there is no way to release the
waiting backend. I think that some solutions for this issue which is likely to
happen are required.

Regards,

--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center