On 9/20/19 6:17 PM, Tom Lane wrote: > Alvaro Herrera <alvhe...@2ndquadrant.com> writes: >> Uh .. I didn't think it was possible that we would build the same >> snapshot file more than once. Isn't that a waste of time anyway? Maybe >> we can fix the symptom by just not doing that in the first place? >> I don't have a strategy to do that, but seems worth considering before >> retiring the bf animals. > The comment near the head of SnapBuildSerialize says > > * there is an obvious race condition here between the time we stat(2) the > * file and us writing the file. But we rename the file into place > * atomically and all files created need to contain the same data anyway, > * so this is perfectly fine, although a bit of a resource waste. Locking > * seems like pointless complication. > > which seems like a reasonable argument. Also, this is hardly the only > place where we expect rename(2) to be atomic. So I tend to agree with > Andres that we should consider OSes with such a bug to be unsupported. > > Dromedary is running the last release of macOS that supports 32-bit > hardware, so if we decide to kick that to the curb, I'd either shut > down the box or put some newer Linux or BSD variant on it. > >
Well, nightjar is on FBSD 9.0 which is oldish. I can replace it before long with an 11-stable instance if that's appropriate. cheers andrew -- Andrew Dunstan https://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
