[SPARK-13958] Executor OOM due to unbounded growth of pointer array in…

## What changes were proposed in this pull request?

This change fixes the executor OOM which was recently introduced in PR apache/spark#11095
(Please fill in changes proposed in this fix)

## How was this patch tested?
Tested by running a spark job on the cluster.
(Please explain how this patch was tested. E.g. unit tests, integration tests, manual tests)

(If this patch involves UI changes, please attach a screenshot; otherwise, remove this)

… Sorter

Author: Sital Kedia <skedia@fb.com>

Closes #11794 from sitalkedia/SPARK-13958.

core/src/main/java/org/apache/spark/shuffle/sort/ShuffleExternalSorter.java

@@ -320,7 +320,18 @@ final class ShuffleExternalSorter extends MemoryConsumer {
     assert(inMemSorter != null);
     if (!inMemSorter.hasSpaceForAnotherRecord()) {
       long used = inMemSorter.getMemoryUsage();
-      LongArray array = allocateArray(used / 8 * 2);
+      LongArray array;
+      try {
+        // could trigger spilling
+        array = allocateArray(used / 8 * 2);
+      } catch (OutOfMemoryError e) {
+        // should have trigger spilling
+        if (!inMemSorter.hasSpaceForAnotherRecord()) {
+          logger.error("Unable to grow the pointer array");
+          throw e;
+        }
+        return;
+      }
       // check if spilling is triggered or not
       if (inMemSorter.hasSpaceForAnotherRecord()) {
         freeArray(array);

core/src/main/java/org/apache/spark/util/collection/unsafe/sort/UnsafeExternalSorter.java

@@ -293,7 +293,18 @@ public final class UnsafeExternalSorter extends MemoryConsumer {
     assert(inMemSorter != null);
     if (!inMemSorter.hasSpaceForAnotherRecord()) {
       long used = inMemSorter.getMemoryUsage();
-      LongArray array = allocateArray(used / 8 * 2);
+      LongArray array;
+      try {
+        // could trigger spilling
+        array = allocateArray(used / 8 * 2);
+      } catch (OutOfMemoryError e) {
+        // should have trigger spilling
+        if (!inMemSorter.hasSpaceForAnotherRecord()) {
+          logger.error("Unable to grow the pointer array");
+          throw e;
+        }
+        return;
+      }
       // check if spilling is triggered or not
       if (inMemSorter.hasSpaceForAnotherRecord()) {
         freeArray(array);