On 9/1/17 7:53 PM, Michael Paquier wrote:
> On Sat, Sep 2, 2017 at 3:06 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> I don't think this really buys us anything. If we'd applied it to v10
>> maybe, but what do we get out of whacking it around now?
>>
>> "Consistency", I hear you cry! Fair point. But we never had a goal
>> of eliminating all internal references to "xlog", just the user-facing
>> ones. And since RECOVERYXLOG is not documented, I think there's a
>> good argument that it's not user-facing. You could argue that since
>> it shows up in the file system it's implicitly user-facing, and maybe
>> you're right; if some other committer really wants to make this
>> change, I won't grouse much. But personally I'd favor leaving it
>> alone to avoid having the behavior change a little bit in every new
>> release.
>
> I may be wrong, but I would suspect that some backup tools doing
> FS-level backup are checking on the existence of this file and skip
> it. From the point of view of operations, it does not matter much as
> any existing RECOVERYXLOG is unlinked before being replaced by a new
> one, but that would not be nice to add silently 16MB in each backup.
Yes, pgBackRest does have an "offline" mode that can be used (when the
database is shutdown) to do an FS-level backup.
It never occurred to me to exclude RECOVERYXLOG but with 1GB WAL
segments coming in v11 it might be a good idea.
--
-David
david@pgmasters.net