[SPARK-39084][PYSPARK] Fix df.rdd.isEmpty() by using TaskContext to s…

…top iterator on task completion

### What changes were proposed in this pull request?

This PR fixes the issue described in https://issues.apache.org/jira/browse/SPARK-39084 where calling `df.rdd.isEmpty()` on a particular dataset could result in a JVM crash and/or executor failure.

The issue was due to Python iterator not being synchronised with Java iterator so when the task is complete, the Python iterator continues to process data. We have introduced ContextAwareIterator as part of https://issues.apache.org/jira/browse/SPARK-33277 but we did not fix all of the places where this should be used.

### Why are the changes needed?

Fixes the JVM crash when checking isEmpty() on a dataset.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

I added a test case that reproduces the issue 100%. I confirmed that the test fails without the fix and passes with the fix.

Closes apache#36425 from sadikovi/fix-pyspark-iter-2.

Authored-by: Ivan Sadikov <[email protected]>
Signed-off-by: Hyukjin Kwon <[email protected]>

python/pyspark/sql/tests/test_dataframe.py

@@ -22,6 +22,7 @@
 import tempfile
 import time
 import unittest
+import uuid
 from typing import cast
 
 from pyspark.sql import SparkSession, Row
@@ -1176,6 +1177,41 @@ def test_df_show(self):
         with self.assertRaisesRegex(TypeError, "Parameter 'truncate=foo'"):
             df.show(truncate="foo")
 
+    def test_df_is_empty(self):
+        # SPARK-39084: Fix df.rdd.isEmpty() resulting in JVM crash.
+
+        # This particular example of DataFrame reproduces an issue in isEmpty call
+        # which could result in JVM crash.
+        data = []
+        for t in range(0, 10000):
+            id = str(uuid.uuid4())
+            if t == 0:
+                for i in range(0, 99):
+                    data.append((id,))
+            elif t < 10:
+                for i in range(0, 75):
+                    data.append((id,))
+            elif t < 100:
+                for i in range(0, 50):
+                    data.append((id,))
+            elif t < 1000:
+                for i in range(0, 25):
+                    data.append((id,))
+            else:
+                for i in range(0, 10):
+                    data.append((id,))
+
+        tmpPath = tempfile.mkdtemp()
+        shutil.rmtree(tmpPath)
+        try:
+            df = self.spark.createDataFrame(data, ["col"])
+            df.coalesce(1).write.parquet(tmpPath)
+
+            res = self.spark.read.parquet(tmpPath).groupBy("col").count()
+            self.assertFalse(res.rdd.isEmpty())
+        finally:
+            shutil.rmtree(tmpPath)
+
     @unittest.skipIf(
         not have_pandas or not have_pyarrow,
         cast(str, pandas_requirement_message or pyarrow_requirement_message),

sql/core/src/main/scala/org/apache/spark/sql/execution/python/EvaluatePython.scala

@@ -24,6 +24,7 @@ import scala.collection.JavaConverters._
 
 import net.razorvine.pickle.{IObjectPickler, Opcodes, Pickler}
 
+import org.apache.spark.{ContextAwareIterator, TaskContext}
 import org.apache.spark.api.python.SerDeUtil
 import org.apache.spark.rdd.RDD
 import org.apache.spark.sql.catalyst.InternalRow
@@ -301,7 +302,7 @@ object EvaluatePython {
   def javaToPython(rdd: RDD[Any]): RDD[Array[Byte]] = {
     rdd.mapPartitions { iter =>
       registerPicklers()  // let it called in executor
-      new SerDeUtil.AutoBatchedPickler(iter)
+      new SerDeUtil.AutoBatchedPickler(new ContextAwareIterator(TaskContext.get, iter))
     }
   }
 }