Re: [Patch] Make pg_checksums skip foreign tablespace directories

On 2/21/20 1:36 AM, Michael Paquier wrote:
> On Thu, Feb 20, 2020 at 05:38:15PM +0100, Bernd Helmle wrote:
>> So i propose a different approach like the attached patch tries to
>> implement: instead of just blindly iterating over directory contents
>> and filter them out, reference the tablespace location and
>> TABLESPACE_VERSION_DIRECTORY directly. This is done by a new function
>> scan_tablespaces() which is specialized in just follow the
>> symlinks/junctions in pg_tblspc and call scan_directory() with just
>> what it has found there. It will also honour directories, just in case
>> an experienced DBA has copied over the tablespace into pg_tblspc
>> directly.
>
> + if (S_ISREG(st.st_mode))
> + {
> + pg_log_debug("ignoring file %s in pg_tblspc", de->d_name);
> + continue;
> + }
> We don't do that for the normal directory scan path, so it does not
> strike me as a good idea on consistency ground. As a whole, I don't
> see much point in having a separate routine which is just roughly a
> duplicate of scan_directory(), and I think that we had better just add
> the check looking for matches with TABLESPACE_VERSION_DIRECTORY
> directly when having a directory, if subdir is "pg_tblspc". That
> also makes the patch much shorter.

+1. This is roughly what pg_basebackup does and it seems simpler to me.

Regards,
--
-David
david(at)pgmasters(dot)net