Multi-column indexes where the second or later column was descending did not…

Multi-column indexes where the second or later column was descending did not always produce correct results.

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,9 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>When using large transactions or a small log size, the database could get very slow
+<ul><li>Multi-column indexes where the second or later column was descending did not always
+    produce correct results (rows were missing in the result set, or the result set was empty).
+</li><li>When using large transactions or a small log size, the database could get very slow
     (profiling shows the hotspot is in FileObjectDisk.sync()).
 </li><li>The Shell tool now prints the stack trace when the list mode is enabled.
 </li><li>CREATE ALIAS ... AS: Compilation was incorrect if the source code contained

h2/src/main/org/h2/index/IndexCursor.java

@@ -49,7 +49,7 @@ public class IndexCursor implements Cursor {
         if (idxCols != null) {
             for (int i = 0; i < columns.length; i++) {
                 int idx = index.getColumnIndex(columns[i]);
-                if (idx == 0) {
+                if (idx >= 0) {
                     indexColumns[i] = idxCols[idx];
                 }
             }

h2/src/test/org/h2/test/db/TestIndex.java

@@ -249,6 +249,13 @@ public class TestIndex extends TestBase {
         rs.next();
         assertEquals(11, rs.getInt(1));
         stat.execute("DROP TABLE TEST");
+
+        stat.execute("create table test(x int, y int)");
+        stat.execute("insert into test values(1, 1), (1, 2)");
+        stat.execute("create index test_x_y on test (x desc, y desc)");
+        rs = stat.executeQuery("select * from test where x=1 and y<2");
+        assertTrue(rs.next());
+
         conn.close();
     }