Robert Haas wrote: > On Sat, Aug 15, 2015 at 6:45 PM, Mark Johnston <ma...@freebsd.org> wrote:
> > The bug is in src/backend/Makefile. probes.o, the dtrace(1)-generated > > object file, depends on the objfiles.txt for each of the backend > > subdirs. These files depend in turn on the object files themselves; if > > objfiles.txt is out of date with respect to one of its object files, the > > mtime of objfiles.txt is updated with "touch" (see backend/common.mk). > > The problem is that dtrace -G, which runs at the end of the build, > > modifies a number of object files (it overwrites their probe sites with > > NOPs), thus making their corresponding objfiles.txt out of date. Then, > > when "make install" traverses the backend subdirs, it updates > > objfiles.txt, which causes probes.o to be rebuilt, resulting in an error > > from dtrace(1). > > Gosh, that's pretty ugly. I would have thought it would be a real > no-no to update the .o file once it got generated. If nothing else, a > modification to the .c file concurrent with a make invocation might > lead to the .o not getting rebuilt the next time make is run. I had the same thought, and wondered for a bit whether we should instead have the compilation rules produce some intermediate file (prior to dtrace fumbling), then emit the .o from dtrace -G. OTOH this might be more trouble than is worth for a feature that doesn't see a lot of use. > > The attached patch fixes the problem by having probes.o depend on object > > files directly, rather than on objfiles.txt. I've tested it with > > PostgreSQL 9.0-9.4 on FreeBSD CURRENT. > > I don't see a particular reason not to make this change, though. I wanted to test it on Linux yesterday but didn't get any further than installing a couple of packages. -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
