Re: [COMMITTERS] pgsql: New SQL functons pg_backup_in_progress() and pg_backup_start_tim

On Fri, Jun 15, 2012 at 11:14 PM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> On 15.06.2012 17:54, Magnus Hagander wrote:
>>
>> On Fri, Jun 15, 2012 at 8:16 PM, Robert Haas<robertmhaas(at)gmail(dot)com>
>>  wrote:
>>>
>>> On Fri, Jun 15, 2012 at 1:52 AM, Magnus Hagander<magnus(at)hagander(dot)net>
>>>  wrote:
>>>>
>>>> On Fri, Jun 15, 2012 at 1:29 AM, Robert Haas<rhaas(at)postgresql(dot)org>
>>>>  wrote:
>>>>>
>>>>> New SQL functons pg_backup_in_progress() and pg_backup_start_time()
>>>>>
>>>>> Darold Gilles, reviewed by Gabriele Bartolini and others, rebased by
>>>>> Marco Nenciarini.  Stylistic cleanup and OID fixes by me.
>>>>
>>>>
>>>> How well is the term "on-line exclusive backup" really settled with
>>>> people? I wonder if we need to add a specific note to the docs saying
>>>> that the function doesn't consider streaming base backups at all, and
>>>> that one should refer to pg_stat_replication for info about those? Or
>>>> really, should the function be pg_exclusive_backup_in_progress()
>>>> perhaps?
>>>
>>>
>>> Well, if we think that the term "exclusive backup" is not going to be
>>> easily comprehensible, then sticking that into the function name isn't
>>> going to help us much.  I think that's just wordiness for the sake of
>>> being wordy.  I do agree that we could probably improve the clarity of
>>> the documentation along the lines you suggest.
>>
>>
>> It would alert people to the existance of the term, and thus help
>> those who didn't actually read the documentation.
>
>
> I'm not sure we want to expose the "exclusive backup" term to users. It's a
> bit confusing. It makes sense in the limited scope in the code in xlog.c
> where it's currently used, but if I wanted to explain what it is to users, I
> don't think I'd choose that term.
>
>
>> Which actually makes an argument for making that change *anyway*,
>> because right now the function is incorrectly named. A function named
>> pg_backup_in_progress() should answer the question "is a backup in
>> progress". And it doesn't answer that question.
>
>
> I agree that pg_backup_in_progress() is confusing, if it returns false while
> you're running pg_basebackup. In the doc changes you proposed, you call the
> pg_start/stop_backup() a "low level API" for taking backups. That's not
> suitable for a function name, but I think we should work on that, and find a
> better term that works.
>
> Backup mode? Filesystem backup mode?

We already have backup mode, and it covers both of them really. And
filesystem backup mode is also what pg_basebackup does - it takes a
filesystem backup...

The easiest one I can think of is the "manual backup mode", but in the
other thread Simon didn't like that term.

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/