Re: Loaded footgun open_datasync on Windows

Michael Paquier wrote:
> On Mon, Sep 10, 2018 at 04:46:40PM +0200, Laurenz Albe wrote:
> > I didn't get pg_upgrade to work without the log file hacks; I suspect
> > that there is more than just log file locking going on, but my Windows
> > skills are limited.
> >
> > How shall I proceed?
>
> I do like this patch, and we have an occasion to clean a bunch of things
> in pg_upgrade, so this argument is enough to me to put my hands in the
> dirt and check by myself, so...
>
> I really thought that this was not ambitious enough, so I have hacked on
> top of your patch, so as pg_upgrade concurrent issues are removed, and I
> have found one barrier in pg_ctl which decides that it is smarter to
> redirect the log file (here pg_upgrade_server.log) using CMD. The
> problem is that the lock taken by the process which does the redirection
> does not work nicely with what pg_upgrade does in parallel. So I think
> that it is better to drop that part.

I got you now.
So I won't try to deal with that at this point.

> +#ifdef WIN32
> + if ((infile = fopen(path, "rt")) == NULL)
> +#else
> if ((infile = fopen(path, "r")) == NULL)
> +#endif
> This should have a comment, saying roughly that as this uses
> win32_fopen, text mode needs to be enforced to get proper CRLF.

Done.

> One spot for open() is missed in file_utils.c, please see
> pre_sync_fname().

Done.

> The patch fails to apply for pg_verify_checksums, with a conflict easy
> enough to fix.

Fixed.

> Laurenz, could you update your patch? I am switching that as waiting on
> author for now.

Attached is the new, improved version of the patch.

Thanks again!

Yours,
Laurenz Albe