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90281a3a28
This fixes a performance problem introduced by commit 6d7547c21. ERROR_ACCESS_DENIED is returned in some other cases besides the delete-pending case considered by that commit; notably, if the given path names a directory instead of a plain file. In that case we'll uselessly loop for 1 second before returning the failure condition. That slows down some usage scenarios enough to cause test timeout failures on our Windows buildfarm critters. To fix, try to stat() the file, and sleep/loop only if that fails. It will fail in the delete-pending case, and also in the case where the deletion completed before we could stat(), so we have the cases where we want to loop covered. In the directory case, the stat() should succeed, letting us exit without a wait. One case where we'll still wait uselessly is if the access-denied problem pertains to a directory in the given pathname. But we don't expect that to happen in any performance-critical code path. There might be room to refine this further, but I'll push it now in hopes of making the buildfarm green again. Back-patch, like the preceding commit. Alexander Lakhin and Tom Lane Discussion: https://postgr.es/m/23073.1576626626@sss.pgh.pa.us
src/port/README
libpgport
=========
libpgport must have special behavior. It supplies functions to both
libraries and applications. However, there are two complexities:
1) Libraries need to use object files that are compiled with exactly
the same flags as the library. libpgport might not use the same flags,
so it is necessary to recompile the object files for individual
libraries. This is done by removing -lpgport from the link line:
# Need to recompile any libpgport object files
LIBS := $(filter-out -lpgport, $(LIBS))
and adding infrastructure to recompile the object files:
OBJS= execute.o typename.o descriptor.o data.o error.o prepare.o memory.o \
connect.o misc.o path.o exec.o \
$(filter strlcat.o, $(LIBOBJS))
The problem is that there is no testing of which object files need to be
added, but missing functions usually show up when linking user
applications.
2) For applications, we use -lpgport before -lpq, so the static files
from libpgport are linked first. This avoids having applications
dependent on symbols that are _used_ by libpq, but not intended to be
exported by libpq. libpq's libpgport usage changes over time, so such a
dependency is a problem. Windows, Linux, and macOS use an export list to
control the symbols exported by libpq.