On Wed, Sep 21, 2011 at 1:13 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Wed, Sep 21, 2011 at 1:08 PM, Josh Berkus <josh@agliodbs.com> wrote:
>> On 9/21/11 10:07 AM, Robert Haas wrote:
>>> On Wed, Sep 21, 2011 at 1:03 PM, Josh Berkus <josh@agliodbs.com> wrote:
>>>>> Yeah, I get it. But I think standby would confuse them, too, just in
>>>>> a different set of situations.
>>>>
>>>> Other than PITR, what situations?
>>>
>>> Hot backup?
>>
>> Hot backup == PITR. You're just not bothering to accumulate WAL logs.
>
> Well, I don't think of it that way, but YMMV, of course.
I think that the major differentiating factor is the "intended action
when caught up", and the definition of caught up, and trying to use a
single term for both of them is going to always cause confusion.
So I tend to think of the use cases by their "continuation". A
"slave" is intended to "continually keep trying to get more" once it's
retrieved and applied all the changes it can. It can be hot, or cold,
streaming, or archive, etc... And "recovery" is intended to stop
recovering and become "normal" once it's finished retrieving and
applying all changes it can. Again, it has multiple ways to retrive
it's wal too.
And I think Tom touched on this point in the
"recovery.conf/recovery.done" thread a bit too. Maybe we need to
really start talking about the different "when done do ..."
distinctions, and and using that distinction to help our nomenclature.
Both recovery/slave (both hot or cold) use the same retrieve/apply
machinery (and thus configuration options). But because of the
different "caught up action", are different features.
a.
--
Aidan Van Dyk Create like a god,
aidan@highrise.ca command like a king,
http://www.highrise.ca/ work like a slave.