On Thu, Dec 29, 2016 at 6:13 PM, Magnus Hagander <magnus@hagander.net> wrote: > On Thu, Dec 29, 2016 at 12:35 AM, Michael Paquier > <michael.paquier@gmail.com> wrote: >> On Wed, Dec 28, 2016 at 9:31 PM, Magnus Hagander <magnus@hagander.net> >> wrote: >> >> - I have switched the directory method to use a file pointer instead >> >> of a file descriptor as gzwrite returns int as the number of >> >> uncompressed bytes written. >> > >> > I don't really follow that reasoning :) Why does the directory method >> > have >> > to change to use a filepointer because of that? >> >> The only reason is that write() returns size_t and fwrite returns int, >> while gzwrite() returns int. It seems more consistent to use fwrite() >> in this case. Or we don't bother about my nitpicking and just cast >> stuff. > > > I can at least partially see that argument, but your patch doesn't actually > use fwrite(), it uses write() with fileno()...
That was part of the one/two things I wanted to change before sending a fresh patch.
OK.
> But also, on my platform (debian jessie), fwrite() returns size_t, and > write() returns ssize_t. So those are apparently both different from what > your platform does - which one did you get that one?
It looks like I misread the macos man pages previously. Thay actually list ssize_t. I find a bit surprising the way gzwrite is designed. It uses an input an unsigned integer and returns to caller a signed integer, so this will never work with uncompressed buffers of sizes higher than 2GB. There's little point to worry about that in pg_receivexlog though, so let's just cast to ssize_t.
Attached is a simplified new version, I have kept the file descriptor as originally done. Note that tests are actually difficult to work out, there is no way to run in batch pg_receivexlog..
A few further notes:
You are using the filemode to gzopen and the mode_compression variable to set the compression level. The pre-existing code in pg_basebackup uses gzsetparams(). Is there a particular reason you didn't do it the same way?
Small comment:
- if (pad_to_size)
+ if (pad_to_size && dir_data->compression == 0)
{
/* Always pre-pad on regular files */
That "always" is not true anymore. Commit-time cleanup can be done of that.
The rest of this looks good to me, but please comment on the gzopen part before we proceed to commit :)
