python - Why does PySpark keeps calliing Iterator.next after the TaskContext is marked as completed? -


i've built connector database , in custom rdd.compute function i'm adding listener taskcontext.addtaskcompletionlistener closes database connection (this seems common practice among spark connectors, spark's hadooprdd uses pattern well).

i have pyspark application creates rdd database data , call rdd.take(1) on rdd (1 partition, 1 local worker thread). problem here pyspark keeps calling iterator.next (custom iterator well) after fired task completion handler.

this doesn't happen when scala application calls same rdd.take(1), spark source code pyspark's rdd.take differs spark's scala rdd.take.

i'd appreciate thoughts on issue.


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