Merge pull request #529 from apache/5.0.X-patch

prep for 5.0.2, fix KllItemsSketch level 0 sorting issue

Author: jmalkin

pom.xml

@@ -33,7 +33,7 @@ under the License.
 
   <groupId>org.apache.datasketches</groupId>
   <artifactId>datasketches-java</artifactId>
-  <version>5.0.1</version>
+  <version>5.0.2</version>
   <packaging>jar</packaging>
 
   <name>${project.artifactId}</name>
@@ -734,7 +734,7 @@ under the License.
         </pluginManagement>
       </build>
     </profile>
-    
+
     <profile>
       <id>check-cpp-historical-files</id>
       <build>

src/main/java/org/apache/datasketches/kll/KllItemsHelper.java

@@ -409,7 +409,7 @@ private static <T> int[] generalItemsCompress(
 
         // level zero might not be sorted, so we must sort it if we wish to compact it
         if ((curLevel == 0) && !isLevelZeroSorted) {
-          Arrays.sort(inBuf, adjBeg, adjBeg + adjPop);
+          Arrays.sort((T[])inBuf, adjBeg, adjBeg + adjPop, comp);
         }
 
         if (popAbove == 0) { // Level above is empty, so halve up
@@ -486,4 +486,3 @@ private static <T> void populateItemWorkArrays(
   //    }
 
 }
-

src/test/java/org/apache/datasketches/kll/KllItemsSketchTest.java

@@ -22,6 +22,7 @@
 import static java.lang.Math.ceil;
 import static org.apache.datasketches.kll.KllSketch.SketchStructure.*;
 import static org.apache.datasketches.kll.KllSketch.SketchType.*;
+import static org.apache.datasketches.quantilescommon.LongsAsOrderableStrings.getString;
 import static org.apache.datasketches.quantilescommon.QuantileSearchCriteria.EXCLUSIVE;
 import static org.apache.datasketches.quantilescommon.QuantileSearchCriteria.INCLUSIVE;
 import static org.testng.Assert.assertEquals;
@@ -31,6 +32,7 @@
 import static org.testng.Assert.fail;
 
 import java.util.Comparator;
+import java.util.Random;
 
 import org.apache.datasketches.common.ArrayOfStringsSerDe;
 import org.apache.datasketches.common.SketchesArgumentException;
@@ -42,6 +44,7 @@
 import org.apache.datasketches.quantilescommon.DoublesSortedView;
 import org.apache.datasketches.quantilescommon.GenericSortedView;
 import org.apache.datasketches.quantilescommon.GenericSortedViewIterator;
+import org.apache.datasketches.quantilescommon.QuantilesGenericSketchIterator;
 import org.testng.annotations.Test;
 
 @SuppressWarnings("unused")
@@ -751,6 +754,34 @@ public void checkSortedViewAfterReset() {
     try { sk.getSortedView(); fail(); } catch (SketchesArgumentException e) { }
   }
 
+  @Test
+  //There is no guarantee that L0 is sorted after a merge.
+  //The issue is, during a merge, L0 must be sorted prior to a compaction to a higher level.
+  //Otherwise the higher levels would not be sorted properly.
+  public void checkL0SortDuringMerge() throws NumberFormatException {
+    final Random rand = new Random();
+    final KllItemsSketch<String> sk1 = KllItemsSketch.newHeapInstance(8, Comparator.reverseOrder(), serDe);
+    final KllItemsSketch<String> sk2 = KllItemsSketch.newHeapInstance(8, Comparator.reverseOrder(), serDe);
+    final int n = 26; //don't change this
+    for (int i = 1; i <= n; i++ ) {
+      final int j = rand.nextInt(n) + 1;
+      sk1.update(getString(j, 3));
+      sk2.update(getString(j +100, 3));
+    }
+    sk1.merge(sk2);
+    println(sk1.toString(true, true)); //L1 and above should be sorted in reverse. Ignore L0.
+    final int lvl1size = sk1.levelsArr[2] - sk1.levelsArr[1];
+    final QuantilesGenericSketchIterator<String> itr = sk1.iterator();
+    itr.next();
+    int prev = Integer.parseInt(itr.getQuantile().trim());
+    for (int i = 1; i < lvl1size; i++) {
+      if (itr.next()) {
+        int v = Integer.parseInt(itr.getQuantile().trim());
+        assertTrue(v <= prev);
+        prev = v;
+      }
+    }
+  }
 
   private final static boolean enablePrinting = false;