Reduce page size to make HiveCompatibilitySuite pass.

Author: JoshRosen

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

@@ -41,7 +41,7 @@ public final class UnsafeExternalSorter {
 
   private final Logger logger = LoggerFactory.getLogger(UnsafeExternalSorter.class);
 
-  private static final int PAGE_SIZE = 1 << 27;  // 128 megabytes
+  private static final int PAGE_SIZE = 1 << 22;  // 4 megabytes
   @VisibleForTesting
   static final int MAX_RECORD_SIZE = PAGE_SIZE - 4;
 

unsafe/src/main/java/org/apache/spark/unsafe/map/BytesToBytesMap.java

@@ -78,7 +78,7 @@ public final class BytesToBytesMap {
    * The size of the data pages that hold key and value data. Map entries cannot span multiple
    * pages, so this limits the maximum entry size.
    */
-  private static final long PAGE_SIZE_BYTES = 1L << 26; // 64 megabytes
+  private static final long PAGE_SIZE_BYTES = 1L << 22; // 4 megabytes
 
   /**
    * The maximum number of keys that BytesToBytesMap supports. The hash table has to be