Re: [HACKERS] Patch to implement pg_current_logfile() function

On Tue, Mar 7, 2017 at 3:21 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Sat, Mar 4, 2017 at 10:32 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Without having actually looked at this patch, I would say that if it added
>> a direct call of fopen() to backend-side code, that was already the wrong
>> thing.  Almost always, AllocateFile() would be a better choice, not only
>> because it's tied into transaction abort, but also because it knows how to
>> release virtual FDs in event of ENFILE/EMFILE errors.  If there is some
>> convincing reason why you shouldn't use AllocateFile(), then a safe
>> cleanup pattern would be to have the fclose() in a PG_CATCH stanza.
>
> I think that my previous remarks on this issue were simply muddled
> thinking.  The SQL-callable function pg_current_logfile() does use
> AllocateFile(), so the ERROR which may occur afterward if the file is
> corrupted is no problem.  The syslogger, on the other hand, uses
> logfile_open() to open the file, but it's careful not to throw an
> ERROR while the file is open, just like other code which runs in the
> syslogger.  So now I think there's no bug here.

-           /*
-            * No space found, file content is corrupted.  Return NULL to the
-            * caller and inform him on the situation.
-            */
+           /* Uh oh.  No newline found, so file content is corrupted. */
This one just made me smile.
-- 
Michael