Tuples emitted between end and begin windows is only one of possible
behaviors that emitting tuples on a separate from the operator thread
may introduce. It will be good to have both checks in place at run-time
and if checking for the operator thread for every emitted tuple is too
expensive, we may have it enabled only in DEBUG or mode with more checks
in place.
Vlad
Sanjay just reminded me of my typo -> I meant between end_window and
start_window :)
Thks
Amol
On Wed, Aug 10, 2016 at 2:36 PM, Sanjay Pujare <[email protected]>
wrote:
If the goal is to do this validation through static analysis of operator
code, I guess it is possible but is going to be non-trivial. And there
could be false positives and false negatives.
Also I suppose this discussion applies to processor operators (those
having both in and out ports) so Ram’s example of JdbcPollInputOperator may
not be applicable here?
On 8/10/16, 2:04 PM, "Ashwin Chandra Putta" <[email protected]>
wrote:
In a separate thread I mean.
Regards,
Ashwin.
On Wed, Aug 10, 2016 at 2:01 PM, Ashwin Chandra Putta <
[email protected]> wrote:
> + [email protected]
> - [email protected]
>
> This is one of those best practices that we learn by experience
during
> operator development. It will save a lot of time during operator
> development if we can catch and throw validation error when someone
emits
> tuples in a non separate thread.
>
> Regards,
> Ashwin
>
> On Wed, Aug 10, 2016 at 1:57 PM, Munagala Ramanath <
[email protected]>
> wrote:
>
>> For cases where use of a different thread is needed, it can write
tuples
>> to a queue from where the operator thread pulls them --
>> JdbcPollInputOperator in Malhar has an example.
>>
>> Ram
>>
>> On Wed, Aug 10, 2016 at 1:50 PM, [email protected] <[email protected]
>> wrote:
>>
>>> Hey Vlad,
>>>
>>> Thanks for bringing this up. Is there an easy way to detect
unexpected
>>> use of emit method without hurt the performance. Or at least if we
can
>>> detect this in debug mode.
>>>
>>> Regards,
>>> Siyuan
>>>
>>> On Wed, Aug 10, 2016 at 11:27 AM, Vlad Rozov <
[email protected]>
>>> wrote:
>>>
>>>> The short answer is no, creating worker thread to emit tuples is
not
>>>> supported by Apex and will lead to an undefined behavior.
Operators in Apex
>>>> have strong thread affinity and all interaction with the platform
must
>>>> happen on the operator thread.
>>>>
>>>> Vlad
>>>>
>>>
>>>
>>
>
>
> --
>
> Regards,
> Ashwin.
>
--
Regards,
Ashwin.
