[SPARK-30556][SQL][2.4] Copy sparkContext.localproperties to child thread inSubqueryExec.executionContext #27340
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What changes were proposed in this pull request?
In
org.apache.spark.sql.execution.SubqueryExec#relationFuture
make a copy oforg.apache.spark.SparkContext#localProperties
and pass it to the sub-execution thread inorg.apache.spark.sql.execution.SubqueryExec#executionContext
Why are the changes needed?
Local properties set via sparkContext are not available as TaskContext properties when executing jobs and threadpools have idle threads which are reused
Explanation:
When
SubqueryExec
, the relationFuture is evaluated via a separate thread. The threads inherit thelocalProperties
fromsparkContext
as they are the child threads.These threads are created in the
executionContext
(thread pools). Each Thread pool has a default keepAliveSeconds of 60 seconds for idle threads.Scenarios where the thread pool has threads which are idle and reused for a subsequent new query, the thread local properties will not be inherited from spark context (thread properties are inherited only on thread creation) hence end up having old or no properties set. This will cause taskset properties to be missing when properties are transferred by child thread via
sparkContext.runJob/submitJob
Does this PR introduce any user-facing change?
No
How was this patch tested?
Added UT