Re: Does parallel make require guards against duplicate actions?

Peter Eisentraut <peter_e(at)gmx(dot)net> writes:
> On mn, 2010-01-04 at 21:58 -0500, Tom Lane wrote:
>> The new implementation uses temp files that just have ".tmp" appended to
>> the target file name. If there is a risk that "make -j" will run the
>> same action twice in parallel, this isn't good enough. While it
>> wouldn't be too tough to add the PID to the scripts, I wonder whether
>> this comment is about a real problem or just a flight of fancy. It
>> doesn't seem to me that parallel make ought to be stupid enough to
>> do the same action twice. Anybody know?

> When you have only one makefile, this shouldn't happen if the rules are
> written correctly. But when the parallel make is initiated from the
> top, plus a decade-old buggy gmake, anything can happen. :-/ It's
> probably worth the small extra effort to be robust against this when the
> alternative is possible slightly butchered catalog files.

OK, I'll go fix that.

regards, tom lane