Re: intermittent test failure on Windows

On 10/21/19 2:58 PM, Tom Lane wrote:
> Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> writes:
>> Bowerbird (Visual Studio 2017 / Windows 10 pro) just had a failure on
>> the pg_ctl test :
>> <https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=bowerbird&dt=2019-10-21%2011%3A50%3A21>
>> I surmise that what's happening here is that the test is trying to read
>> current_logfiles while the server is writing it, so there's a race
>> condition.
> Hmm ... the server tries to replace current_logfiles atomically
> with rename(), so this says that rename isn't atomic on Windows,
> which we knew already. Previous discussion (cf. commit d611175e5)
> implies that an even worse failure condition is possible: the server
> might fail to rename current_logfiles.tmp into place, just because
> somebody is trying to read current_logfiles. Ugh.
>
> I found a thread about trying to make a really bulletproof rename()
> for Windows:
>
> https://www.postgresql.org/message-id/flat/CAPpHfds7dyuGZt%2BPF2GL9qSSVV0OZnjNwqiCPjN7mirDw882tA%40mail.gmail.com
>
> but it looks like we gave up in disgust.

Yeah. Looks like Alexander revived the discussion with a patch back in
August, though, and it's in the next commitfest.
<https://commitfest.postgresql.org/25/2230/>

cheers

andrew

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Andrew Dunstan https://www.2ndQuadrant.com
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