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From Pramod Immaneni <pra...@datatorrent.com>
Subject Re: Why is Async checkpointing made default?
Date Fri, 11 Dec 2015 17:47:10 GMT
There is a pull request for that :)

> On Dec 11, 2015, at 9:43 AM, Thomas Weise <thomas@datatorrent.com> wrote:
>
> I think we should focus on getting APEXCORE-78 done instead. It will
> address a number of existing use cases, including those where we tried to
> utilize checkpointed(...).
>
>
> On Fri, Dec 11, 2015 at 9:36 AM, Chandni Singh <chandni@datatorrent.com>
> wrote:
>
>> Hi,
>>
>> There hasn't been a close bracket here (borrowing Ram's expression :-) ).
>> From what I see the majority agrees with making the fix.
>>
>> Do we need to start a vote for this?
>>
>> On Fri, Nov 27, 2015 at 3:00 PM, Thomas Weise <thomas@datatorrent.com>
>> wrote:
>>
>>> Chetan,
>>>
>>> Would like to understand how the checkpointed callback helps you with
>> what
>>> you indicated. This may require a specific example. Let's take it
>> offline.
>>>
>>> Thomas
>>>
>>> On Wed, Nov 25, 2015 at 4:07 PM, Chetan Narsude (cnarsude) <
>>> cnarsude@cisco.com> wrote:
>>>
>>>> Yes - a few but cannot share the details - protected under NDA - ping
>> me
>>>> in private and I can probably be able to give you more generic details
>> on
>>>> similar cooked up examples.
>>>>
>>>> The part that follows “e.g.” below is an example that probably is
>>>> sufficient to infer the use case logically, I think. I shared that to
>>>> exemplify how changing the semantics will break semver.
>>>>
>>>> —
>>>> Chetan
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>> On 11/25/15, 3:51 PM, "Thomas Weise" <thomas@datatorrent.com> wrote:
>>>>>
>>>>> Do you have a specific example?
>>>>>
>>>>> I see this happening in committed(), but not in checkpointed() where
>> the
>>>>> checkpoint remains intermediate, whether it was copied to HDFS or not.
>>>>>
>>>>>
>>>>> On Wed, Nov 25, 2015 at 3:42 PM, Chetan Narsude (cnarsude) <
>>>>> cnarsude@cisco.com> wrote:
>>>>>
>>>>>>>
>>>>>>> Until we have this, how about we restore the previous behavior
>>>>>>> temporarily?
>>>>>>> Calling checkpointed() immediately does not seem to pose any
>>> practical
>>>>>>> issue but ensures that the code that was written under this
>>> assumption
>>>>>> is
>>>>>>> not broken.
>>>>>>
>>>>>> We can¹t do it. It would be incorrect. It breaks all the other code
>>> that
>>>>>> (unassumingly) correctly complied to the semantics. e.g. an operator
>>>>>> which
>>>>>> informs interesting parties that the checkpointed data is available
>>> for
>>>>>> immediate consumption from storage.
>>>>>>
>>>>>> ‹
>>>>>> Chetan
>>>>>>
>>>>>>
>>>>
>>>>
>>>
>>

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