Re: EINTR error in SunOS

[Qingqing Zhou <zhouqq(at)cs(dot)toronto(dot)edu>]

On Fri, 30 Dec 2005, Tom Lane wrote:
>
> I've heard of this in connection with NFS ... is your DB on an NFS
> filesystem by any chance?
>

I have patched IO routines in backend/storage that POSIX says EINTR is
possible except unlink(). Though POSIX says EINTR is not possible, during
many regressions, I found it sometimes sets this errno on NFS (I still
don't know where is the smoking-gun):

  TRUNCATE TABLE trunc_c,trunc_d,trunc_e;       -- ok
+ WARNING:  could not remove relation 1663/16384/37822: Interrupted system call

There are many other unlink() scattered in backend, some even without
error check. Shall we patch pg_unlink for this situation and replace them
like this:

	pg_unlink(const char* path, int errlevel)
	{
retry:
		returnCode = unlink(path);
		if (returnCode < 0 && errno==EINTR)
			goto retry;

		if other_errors
			elog(elevel, ...);

		return returnCode;
	}

Or

	pg_unlink(const char* path)
	{
		/* no elog -- but we still have to do error check */
	}

Or

	let it be ...

If we decide to do something for unlink(), then we'd better do something
for other EINTR-possible IO routines for fairness :-)

By the way, seems POSIX is not very consistent with EINTR. For example,
closedir() can set EINTR, but opendir()/readdir() can't. Any magic in it?

Regards,
Qingqing