Merge pull request #1328 from h2database/issue#1327

Change MVSecondaryIndex uniqueness check

h2/src/main/org/h2/expression/Comparison.java

@@ -465,12 +465,16 @@ public class Comparison extends Condition {
         }
         if (addIndex) {
             if (l != null) {
-                filter.addIndexCondition(
-                        IndexCondition.get(compareType, l, right));
+                if (l.getType() == right.getType() || right.getType() != Value.STRING_IGNORECASE) {
+                    filter.addIndexCondition(
+                            IndexCondition.get(compareType, l, right));
+                }
             } else if (r != null) {
-                int compareRev = getReversedCompareType(compareType);
-                filter.addIndexCondition(
-                        IndexCondition.get(compareRev, r, left));
+                if (r.getType() == left.getType() || left.getType() != Value.STRING_IGNORECASE) {
+                    int compareRev = getReversedCompareType(compareType);
+                    filter.addIndexCondition(
+                            IndexCondition.get(compareRev, r, left));
+                }
             }
         }
     }

h2/src/main/org/h2/expression/ExpressionColumn.java

@@ -199,7 +199,7 @@ public class ExpressionColumn extends Expression {
 
     @Override
     public int getType() {
-        return column.getType();
+        return column == null ? Value.UNKNOWN : column.getType();
     }
 
     @Override

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

@@ -60,7 +60,7 @@ class MVPlainTempResult extends MVTempResult {
      */
     MVPlainTempResult(Database database, Expression[] expressions, int visibleColumnCount) {
         super(database, expressions.length, visibleColumnCount);
-        ValueDataType valueType = new ValueDataType(database.getCompareMode(), database, new int[columnCount]);
+        ValueDataType valueType = new ValueDataType(database, new int[columnCount]);
         Builder<Long, ValueArray> builder = new MVMap.Builder<Long, ValueArray>()
                                                 .valueType(valueType).singleWriter();
         map = store.openMap("tmp", builder);

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

@@ -51,9 +51,8 @@ public class MVPrimaryIndex extends BaseIndex {
         for (int i = 0; i < columns.length; i++) {
             sortTypes[i] = SortOrder.ASCENDING;
         }
-        ValueDataType keyType = new ValueDataType(null, null, null);
-        ValueDataType valueType = new ValueDataType(db.getCompareMode(), db,
-                sortTypes);
+        ValueDataType keyType = new ValueDataType();
+        ValueDataType valueType = new ValueDataType(db, sortTypes);
         mapName = "table." + getId();
         Transaction t = mvTable.getTransactionBegin();
         dataMap = t.openMap(mapName, keyType, valueType);

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

@@ -62,9 +62,8 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
             sortTypes[i] = columns[i].sortType;
         }
         sortTypes[keyColumns - 1] = SortOrder.ASCENDING;
-        ValueDataType keyType = new ValueDataType(
-                db.getCompareMode(), db, sortTypes);
-        ValueDataType valueType = new ValueDataType(null, null, null);
+        ValueDataType keyType = new ValueDataType(db, sortTypes);
+        ValueDataType valueType = new ValueDataType();
         Transaction t = mvTable.getTransactionBegin();
         dataMap = t.openMap(mapName, keyType, valueType);
         dataMap.map.setVolatile(!indexType.isPersistent());
@@ -128,25 +127,18 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
         for (String bufferName : bufferNames) {
             Iterator<ValueArray> iter = openMap(bufferName).keyIterator(null);
             if (iter.hasNext()) {
-                queue.add(new Source(iter));
+                queue.offer(new Source(iter));
             }
         }
 
         try {
             while (!queue.isEmpty()) {
-                Source s = queue.remove();
+                Source s = queue.poll();
                 ValueArray rowData = s.next();
+                SearchRow row = convertToSearchRow(rowData);
 
-                if (indexType.isUnique()) {
-                    Value[] array = rowData.getList();
-                    // don't change the original value
-                    array = array.clone();
-                    array[keyColumns - 1] = ValueLong.MIN;
-                    ValueArray unique = ValueArray.get(array);
-                    SearchRow row = convertToSearchRow(rowData);
-                    if (!mayHaveNullDuplicates(row)) {
-                        requireUnique(row, dataMap, unique);
-                    }
+                if (indexType.isUnique() && !mayHaveNullDuplicates(row)) {
+                    checkUnique(dataMap, rowData, Long.MIN_VALUE);
                 }
 
                 dataMap.putCommitted(rowData, ValueNull.INSTANCE);
@@ -169,9 +161,8 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
             sortTypes[i] = indexColumns[i].sortType;
         }
         sortTypes[keyColumns - 1] = SortOrder.ASCENDING;
-        ValueDataType keyType = new ValueDataType(
-                database.getCompareMode(), database, sortTypes);
-        ValueDataType valueType = new ValueDataType(null, null, null);
+        ValueDataType keyType = new ValueDataType(database, sortTypes);
+        ValueDataType valueType = new ValueDataType();
         MVMap.Builder<ValueArray, Value> builder =
                 new MVMap.Builder<ValueArray, Value>()
                         .singleWriter()
@@ -195,50 +186,35 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
     public void add(Session session, Row row) {
         TransactionMap<Value, Value> map = getMap(session);
         ValueArray array = convertToKey(row);
-        ValueArray unique = null;
-        if (indexType.isUnique()) {
-            // this will detect committed entries only
-            unique = convertToKey(row);
-            unique.getList()[keyColumns - 1] = ValueLong.MIN;
-            if (mayHaveNullDuplicates(row)) {
-                // No further unique checks required
-                unique = null;
-            } else {
-                requireUnique(row, map, unique);
-            }
+        boolean checkRequired = indexType.isUnique() && !mayHaveNullDuplicates(row);
+        if (checkRequired) {
+            checkUnique(map, array, Long.MIN_VALUE);
         }
+
         try {
             map.put(array, ValueNull.INSTANCE);
         } catch (IllegalStateException e) {
             throw mvTable.convertException(e);
         }
-        if (unique != null) {
-            // This code expects that mayHaveDuplicates(row) == false
-            Iterator<Value> it = map.keyIterator(unique, null, true);
-            while (it.hasNext()) {
-                ValueArray k = (ValueArray) it.next();
-                if (compareRows(row, convertToSearchRow(k)) != 0) {
-                    break;
-                }
-                if (map.isSameTransaction(k)) {
-                    continue;
-                }
-                if (map.get(k) != null) {
-                    // committed
-                    throw getDuplicateKeyException(k.toString());
-                }
-                throw DbException.get(ErrorCode.CONCURRENT_UPDATE_1, table.getName());
-            }
+
+        if (checkRequired) {
+            checkUnique(map, array, row.getKey());
         }
     }
 
-    private void requireUnique(SearchRow row, TransactionMap<Value, Value> map, ValueArray unique) {
-        Value key = map.ceilingKey(unique);
-        if (key != null) {
-            ValueArray k = (ValueArray) key;
-            if (compareRows(row, convertToSearchRow(k)) == 0) {
-                // committed
-                throw getDuplicateKeyException(k.toString());
+    private void checkUnique(TransactionMap<Value, Value> map, ValueArray row, long newKey) {
+        Iterator<Value> it = map.keyIterator(convertToKey(row, Boolean.FALSE), convertToKey(row, Boolean.TRUE), true);
+        while (it.hasNext()) {
+            ValueArray rowData = (ValueArray)it.next();
+            Value[] array = rowData.getList();
+            Value rowKey = array[array.length - 1];
+            long rowId = rowKey.getLong();
+            if (newKey != rowId) {
+                if (map.get(rowData) != null) {
+                    // committed
+                    throw getDuplicateKeyException(rowKey.toString());
+                }
+                throw DbException.get(ErrorCode.CONCURRENT_UPDATE_1, table.getName());
             }
         }
     }
@@ -285,58 +261,23 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
     }
 
     private Cursor find(Session session, SearchRow first, boolean bigger, SearchRow last) {
-        ValueArray min = convertToKey(first);
-        if (min != null) {
-            min.getList()[keyColumns - 1] = ValueLong.MIN;
+        ValueArray min = convertToKey(convertToKey(first), bigger);
+        ValueArray max = convertToKey(convertToKey(last), Boolean.TRUE);
+        TransactionMap<Value,Value> map = getMap(session);
+        return new MVStoreCursor(session, map.keyIterator(min, max, false));
+    }
+
+    private static ValueArray convertToKey(ValueArray r, Boolean minmax) {
+        if (r == null) {
+            return null;
         }
-        TransactionMap<Value, Value> map = getMap(session);
-        if (bigger && min != null) {
-            // search for the next: first skip 1, then 2, 4, 8, until
-            // we have a higher key; then skip 4, 2,...
-            // (binary search), until 1
-            int offset = 1;
-            while (true) {
-                ValueArray v = (ValueArray) map.relativeKey(min, offset);
-                if (v != null) {
-                    boolean foundHigher = false;
-                    for (int i = 0; i < keyColumns - 1; i++) {
-                        int idx = columnIds[i];
-                        Value b = first.getValue(idx);
-                        if (b == null) {
-                            break;
-                        }
-                        Value a = v.getList()[i];
-                        if (database.compare(a, b) > 0) {
-                            foundHigher = true;
-                            break;
-                        }
-                    }
-                    if (!foundHigher) {
-                        offset += offset;
-                        min = v;
-                        continue;
-                    }
-                }
-                if (offset > 1) {
-                    offset /= 2;
-                    continue;
-                }
-                if (map.get(v) == null) {
-                    min = (ValueArray) map.higherKey(min);
-                    if (min == null) {
-                        break;
-                    }
-                    continue;
-                }
-                min = v;
-                break;
-            }
-            if (min == null) {
-                return new MVStoreCursor(session,
-                        Collections.<Value>emptyIterator(), null);
-            }
+
+        Value[] values = r.getList().clone();
+        ValueArray row = ValueArray.get(values);
+        if (minmax != null) {
+            values[values.length - 1] = ValueLong.get(minmax ? Long.MAX_VALUE : Long.MIN_VALUE);
         }
-        return new MVStoreCursor(session, map.keyIterator(min), last);
+        return row;
     }
 
     private ValueArray convertToKey(SearchRow r) {
@@ -349,7 +290,7 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
             int idx = c.getColumnId();
             Value v = r.getValue(idx);
             if (v != null) {
-                array[i] = v.convertTo(c.getType(), -1, null, database.getMode(), c.getEnumerators());
+                array[i] = v.convertTo(c.getType(), -1, database.getMode(), null, c.getEnumerators());
             }
         }
         array[keyColumns - 1] = ValueLong.get(r.getKey());
@@ -420,7 +361,7 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
         while (true) {
             if (key == null) {
                 return new MVStoreCursor(session,
-                        Collections.<Value>emptyIterator(), null);
+                        Collections.<Value>emptyIterator());
             }
             if (((ValueArray) key).getList()[0] != ValueNull.INSTANCE) {
                 break;
@@ -428,7 +369,7 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
             key = first ? map.higherKey(key) : map.lowerKey(key);
         }
         MVStoreCursor cursor = new MVStoreCursor(session,
-                                Collections.singletonList(key).iterator(), null);
+                                Collections.singletonList(key).iterator());
         cursor.next();
         return cursor;
     }
@@ -499,23 +440,20 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
 
         private final Session session;
         private final Iterator<Value> it;
-        private final SearchRow last;
-        private Value current;
-        private SearchRow searchRow;
+        private ValueArray current;
         private Row row;
 
-        MVStoreCursor(Session session, Iterator<Value> it, SearchRow last) {
+        MVStoreCursor(Session session, Iterator<Value> it) {
             this.session = session;
             this.it = it;
-            this.last = last;
         }
 
         @Override
         public Row get() {
             if (row == null) {
-                SearchRow r = getSearchRow();
-                if (r != null) {
-                    row = mvTable.getRow(session, r.getKey());
+                if (current != null) {
+                    Value[] values = current.getList();
+                    row = mvTable.getRow(session, values[values.length - 1].getLong());
                 }
             }
             return row;
@@ -523,24 +461,12 @@ public final class MVSecondaryIndex extends BaseIndex implements MVIndex {
 
         @Override
         public SearchRow getSearchRow() {
-            if (searchRow == null) {
-                if (current != null) {
-                    searchRow = convertToSearchRow((ValueArray) current);
-                }
-            }
-            return searchRow;
+            return current == null ? null : convertToSearchRow(current);
         }
 
         @Override
         public boolean next() {
-            current = it.hasNext() ? it.next() : null;
-            searchRow = null;
-            if (current != null) {
-                if (last != null && compareRows(getSearchRow(), last) > 0) {
-                    searchRow = null;
-                    current = null;
-                }
-            }
+            current = it.hasNext() ? (ValueArray)it.next() : null;
             row = null;
             return current != null;
         }

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

@@ -166,12 +166,12 @@ class MVSortedTempResult extends MVTempResult {
             indexes = null;
         }
         this.indexes = indexes;
-        ValueDataType keyType = new ValueDataType(database.getCompareMode(), database, sortTypes);
+        ValueDataType keyType = new ValueDataType(database, sortTypes);
         Builder<ValueArray, Long> builder = new MVMap.Builder<ValueArray, Long>().keyType(keyType);
         map = store.openMap("tmp", builder);
         if (distinct && length != visibleColumnCount || distinctIndexes != null) {
             int count = distinctIndexes != null ? distinctIndexes.length : visibleColumnCount;
-            ValueDataType distinctType = new ValueDataType(database.getCompareMode(), database, new int[count]);
+            ValueDataType distinctType = new ValueDataType(database, new int[count]);
             Builder<ValueArray, Boolean> indexBuilder = new MVMap.Builder<ValueArray, Boolean>().keyType(distinctType);
             index = store.openMap("idx", indexBuilder);
         }

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

@@ -93,7 +93,7 @@ public class MVSpatialIndex extends BaseIndex implements SpatialIndex, MVIndex {
             checkIndexColumnTypes(columns);
         }
         String mapName = "index." + getId();
-        ValueDataType vt = new ValueDataType(null, null, null);
+        ValueDataType vt = new ValueDataType(db, null);
         VersionedValue.Type valueType = new VersionedValue.Type(vt);
         MVRTreeMap.Builder<VersionedValue> mapBuilder =
                 new MVRTreeMap.Builder<VersionedValue>().

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

@@ -160,9 +160,8 @@ public class MVTableEngine implements TableEngine {
                 if (!db.getSettings().reuseSpace) {
                     store.setReuseSpace(false);
                 }
-                this.transactionStore = new TransactionStore(
-                        store,
-                        new ValueDataType(db.getCompareMode(), db, null), db.getLockTimeout());
+                this.transactionStore = new TransactionStore(store,
+                        new ValueDataType(db, null), db.getLockTimeout());
             } catch (IllegalStateException e) {
                 throw convertIllegalStateException(e);
             }

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

@@ -12,7 +12,10 @@ import java.sql.ResultSet;
 import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.util.Arrays;
+import java.util.Objects;
 import org.h2.api.ErrorCode;
+import org.h2.engine.Database;
+import org.h2.engine.Mode;
 import org.h2.message.DbException;
 import org.h2.mvstore.DataUtils;
 import org.h2.mvstore.WriteBuffer;
@@ -33,6 +36,7 @@ import org.h2.value.ValueBytes;
 import org.h2.value.ValueDate;
 import org.h2.value.ValueDecimal;
 import org.h2.value.ValueDouble;
+import org.h2.value.ValueEnum;
 import org.h2.value.ValueFloat;
 import org.h2.value.ValueGeometry;
 import org.h2.value.ValueInt;
@@ -73,12 +77,22 @@ public class ValueDataType implements DataType {
 
     final DataHandler handler;
     final CompareMode compareMode;
+    protected final Mode mode;
     final int[] sortTypes;
     SpatialDataType spatialType;
 
-    public ValueDataType(CompareMode compareMode, DataHandler handler,
+    public ValueDataType() {
+        this(CompareMode.getInstance(null, 0), Mode.getRegular(), null, null);
+    }
+
+    public ValueDataType(Database database, int[] sortTypes) {
+        this(database.getCompareMode(), database.getMode(), database, sortTypes);
+    }
+
+    private ValueDataType(CompareMode compareMode, Mode mode, DataHandler handler,
             int[] sortTypes) {
         this.compareMode = compareMode;
+        this.mode = mode;
         this.handler = handler;
         this.sortTypes = sortTypes;
     }
@@ -103,7 +117,13 @@ public class ValueDataType implements DataType {
             int len = Math.min(al, bl);
             for (int i = 0; i < len; i++) {
                 int sortType = sortTypes == null ? SortOrder.ASCENDING : sortTypes[i];
-                int comp = compareValues(ax[i], bx[i], sortType);
+                Value one = ax[i];
+                Value two = bx[i];
+                if (one == null || two == null) {
+                    return compareValues(ax[len - 1], bx[len - 1], SortOrder.ASCENDING);
+                }
+
+                int comp = compareValues(one, two, sortType);
                 if (comp != 0) {
                     return comp;
                 }
@@ -136,7 +156,18 @@ public class ValueDataType implements DataType {
         if (aNull || bNull) {
             return SortOrder.compareNull(aNull, sortType);
         }
+
+        int t2 = Value.getHigherOrder(a.getType(), b.getType());
+        if (t2 == Value.ENUM) {
+            String[] enumerators = ValueEnum.getEnumeratorsForBinaryOperation(a, b);
+            a = a.convertToEnum(enumerators);
+            b = b.convertToEnum(enumerators);
+        } else {
+            a = a.convertTo(t2, -1, mode);
+            b = b.convertTo(t2, -1, mode);
+        }
         int comp = a.compareTypeSafe(b, compareMode);
+
         if ((sortType & SortOrder.DESCENDING) != 0) {
             comp = -comp;
         }

h2/src/main/org/h2/tools/Recover.java

@@ -616,18 +616,14 @@ public class Recover extends Tool implements DataHandler {
         }
         try {
             // extract the metadata so we can dump the settings
+            ValueDataType type = new ValueDataType();
             for (String mapName : mv.getMapNames()) {
                 if (!mapName.startsWith("table.")) {
                     continue;
                 }
                 String tableId = mapName.substring("table.".length());
                 if (Integer.parseInt(tableId) == 0) {
-                    ValueDataType keyType = new ValueDataType(
-                            null, this, null);
-                    ValueDataType valueType = new ValueDataType(
-                            null, this, null);
-                    TransactionMap<Value, Value> dataMap = store.begin().openMap(
-                            mapName, keyType, valueType);
+                    TransactionMap<Value, Value> dataMap = store.begin().openMap(mapName, type, type);
                     Iterator<Value> dataIt = dataMap.keyIterator(null);
                     while (dataIt.hasNext()) {
                         Value rowId = dataIt.next();
@@ -660,12 +656,7 @@ public class Recover extends Tool implements DataHandler {
                 if (Integer.parseInt(tableId) == 0) {
                     continue;
                 }
-                ValueDataType keyType = new ValueDataType(
-                        null, this, null);
-                ValueDataType valueType = new ValueDataType(
-                        null, this, null);
-                TransactionMap<Value, Value> dataMap = store.begin().openMap(
-                        mapName, keyType, valueType);
+                TransactionMap<Value, Value> dataMap = store.begin().openMap(mapName, type, type);
                 Iterator<Value> dataIt = dataMap.keyIterator(null);
                 boolean init = false;
                 while (dataIt.hasNext()) {

h2/src/test/org/h2/test/scripts/testScript.sql

@@ -2866,7 +2866,7 @@ CREATE TABLE TEST2(ID INT PRIMARY KEY, NAME VARCHAR(255));
 create unique index idx_test2_name on test2(name);
 > ok
 
-INSERT INTO TEST2 VALUES(1, 'HElLo');
+INSERT INTO TEST2 VALUES(1, 'hElLo');
 > update count: 1
 
 INSERT INTO TEST2 VALUES(2, 'World');
@@ -2886,7 +2886,7 @@ select * from test where name='HELLO';
 select * from test2 where name='HELLO';
 > ID NAME
 > -- -----
-> 1  HElLo
+> 1  hElLo
 > rows: 1
 
 select * from test where name like 'HELLO';
@@ -2897,26 +2897,26 @@ select * from test where name like 'HELLO';
 select * from test2 where name like 'HELLO';
 > ID NAME
 > -- -----
-> 1  HElLo
+> 1  hElLo
 > rows: 1
 
 explain plan for select * from test2, test where test2.name = test.name;
->> SELECT TEST2.ID, TEST2.NAME, TEST.ID, TEST.NAME FROM PUBLIC.TEST2 /* PUBLIC.TEST2.tableScan */ INNER JOIN PUBLIC.TEST /* PUBLIC.IDX_TEST_NAME: NAME = TEST2.NAME */ ON 1=1 WHERE TEST2.NAME = TEST.NAME
+>> SELECT TEST2.ID, TEST2.NAME, TEST.ID, TEST.NAME FROM PUBLIC.TEST2 /* PUBLIC.TEST2.tableScan */ INNER JOIN PUBLIC.TEST /* PUBLIC.TEST.tableScan */ ON 1=1 WHERE TEST2.NAME = TEST.NAME
 
 select * from test2, test where test2.name = test.name;
 > ID NAME  ID NAME
 > -- ----- -- -----
-> 1  HElLo 1  Hello
+> 1  hElLo 1  Hello
 > 2  World 2  World
 > rows: 2
 
 explain plan for select * from test, test2 where test2.name = test.name;
->> SELECT TEST.ID, TEST.NAME, TEST2.ID, TEST2.NAME FROM PUBLIC.TEST2 /* PUBLIC.TEST2.tableScan */ INNER JOIN PUBLIC.TEST /* PUBLIC.IDX_TEST_NAME: NAME = TEST2.NAME */ ON 1=1 WHERE TEST2.NAME = TEST.NAME
+>> SELECT TEST.ID, TEST.NAME, TEST2.ID, TEST2.NAME FROM PUBLIC.TEST2 /* PUBLIC.TEST2.tableScan */ INNER JOIN PUBLIC.TEST /* PUBLIC.TEST.tableScan */ ON 1=1 WHERE TEST2.NAME = TEST.NAME
 
 select * from test, test2 where test2.name = test.name;
 > ID NAME  ID NAME
 > -- ----- -- -----
-> 1  Hello 1  HElLo
+> 1  Hello 1  hElLo
 > 2  World 2  World
 > rows: 2
 
@@ -2924,12 +2924,12 @@ create index idx_test2_name on test2(name);
 > ok
 
 explain plan for select * from test2, test where test2.name = test.name;
->> SELECT TEST2.ID, TEST2.NAME, TEST.ID, TEST.NAME FROM PUBLIC.TEST2 /* PUBLIC.TEST2.tableScan */ INNER JOIN PUBLIC.TEST /* PUBLIC.IDX_TEST_NAME: NAME = TEST2.NAME */ ON 1=1 WHERE TEST2.NAME = TEST.NAME
+>> SELECT TEST2.ID, TEST2.NAME, TEST.ID, TEST.NAME FROM PUBLIC.TEST /* PUBLIC.TEST.tableScan */ INNER JOIN PUBLIC.TEST2 /* PUBLIC.IDX_TEST2_NAME: NAME = TEST.NAME */ ON 1=1 WHERE TEST2.NAME = TEST.NAME
 
 select * from test2, test where test2.name = test.name;
 > ID NAME  ID NAME
 > -- ----- -- -----
-> 1  HElLo 1  Hello
+> 1  hElLo 1  Hello
 > 2  World 2  World
 > rows: 2
 
@@ -2939,7 +2939,7 @@ explain plan for select * from test, test2 where test2.name = test.name;
 select * from test, test2 where test2.name = test.name;
 > ID NAME  ID NAME
 > -- ----- -- -----
-> 1  Hello 1  HElLo
+> 1  Hello 1  hElLo
 > 2  World 2  World
 > rows: 2