MVStore: descending indexes with "nulls first" did not work as expected (null was ordered last).

h2/src/docsrc/html/changelog.html

@@ -18,7 +18,9 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>Large result sets now always create temporary tables instead of temporary files.
+<ul><li>MVStore: descending indexes with "nulls first" did not work as expected
+    (null was ordered last).
+</li><li>Large result sets now always create temporary tables instead of temporary files.
 </li><li>When using the PageStore, opening a database failed in some cases with a NullPointerException
     if temporary tables were used (explicitly, or implicitly when using large result sets).
 </li><li>If a database file in the PageStore file format exists, this file and this mode

h2/src/main/org/h2/mvstore/db/TransactionStore.java

@@ -762,6 +762,10 @@ public class TransactionStore {
          * Commit the transaction. Afterwards, this transaction is closed.
          */
         public void commit() {
+            if (status == STATUS_CLOSED) {
+                // TODO analyze why this happens
+                return;
+            }
             checkNotClosed();
             store.commit(this, logId);
         }

h2/src/main/org/h2/mvstore/db/ValueDataType.java

@@ -115,7 +115,8 @@ public class ValueDataType implements DataType {
         if (a == b) {
             return 0;
         }
-        boolean aNull = a == null, bNull = b == null;
+        boolean aNull = a == null || a == ValueNull.INSTANCE;
+        boolean bNull = b == null || b == ValueNull.INSTANCE;
         if (aNull || bNull) {
             return SortOrder.compareNull(aNull, sortType);
         }

h2/src/main/org/h2/result/ResultTempTable.java

@@ -17,11 +17,9 @@ import org.h2.expression.Expression;
 import org.h2.index.Cursor;
 import org.h2.index.Index;
 import org.h2.index.IndexType;
-import org.h2.index.PageBtreeIndex;
 import org.h2.schema.Schema;
 import org.h2.table.Column;
 import org.h2.table.IndexColumn;
-import org.h2.table.RegularTable;
 import org.h2.table.Table;
 import org.h2.value.Value;
 import org.h2.value.ValueNull;
@@ -114,16 +112,9 @@ public class ResultTempTable implements ResultExternal {
                 table, Constants.PREFIX_INDEX);
         int indexId = session.getDatabase().allocateObjectId();
         IndexType indexType = IndexType.createNonUnique(true);
-        if (session.getDatabase().getMvStore() != null) {
-            index = table.addIndex(session, indexName, indexId, indexCols,
-                    indexType, true, null);
-            index.setTemporary(true);
-        } else {
-            index = new PageBtreeIndex((RegularTable) table, indexId,
-                    indexName, indexCols, indexType, true, session);
-            index.setTemporary(true);
-            table.getIndexes().add(index);
-        }
+        index = table.addIndex(session, indexName, indexId, indexCols,
+                indexType, true, null);
+        index.setTemporary(true);
     }
 
     @Override
@@ -301,10 +292,10 @@ public class ResultTempTable implements ResultExternal {
             createIndex();
         }
         Cursor cursor = index.find(session, row, row);
-        Database db = session.getDatabase();
         while (cursor.next()) {
             SearchRow found = cursor.getSearchRow();
             boolean ok = true;
+            Database db = session.getDatabase();
             for (int i = 0; i < row.getColumnCount(); i++) {
                 if (!db.areEqual(row.getValue(i), found.getValue(i))) {
                     ok = false;