Hi Hongyuan,
it seems as if PyFlink's datastream API is still lacking window support
[1], which is targeted for next release.
Examples for windows in PyFlink's table API are available here [2].
from pyflink.table.window import Tumblefrom pyflink.table.expressions
import lit, col
orders = t_env.from_path("Orders")result =
orders.window(Tumble.over(lit(5).minutes).on(orders.rowtime).alias("w"))
\
.group_by(orders.a, col('w')) \
.select(orders.a, col('w').start, col('w').end,
orders.b.sum.alias('d'))
[1] https://issues.apache.org/jira/browse/FLINK-21202
[2]
https://ci.apache.org/projects/flink/flink-docs-release-1.12/dev/python/table-api-users-guide/operations.html#aggregations
On Fri, Feb 19, 2021 at 8:26 AM Hongyuan Ma <cs_maleica...@163.com> wrote:
> Greetings,
>
> I am a newbie to pyflink. I want to be able to use processWindowFunction
> in a Tumble Window, and finally output 0 or more lines. I have checked the
> datastreamAPI and TableAPI of pyflink, but have not found a complete
> example. pyflink's datastream API does not seem to implement window() yet.
> And I'm not sure how to use TableAPI.
>
> If I use java to implement "public class MyProcessWindowFunctextends
> ProcessWindowFunction” and registered as udf in python,
> is it possible to call it through select statement in pyflink? Can the
> select statement correctly return zero or more rows of results?
>
> Any help will be appreciated!
>
> -----
> Best Regards,
> Hongyuan Ma
>
