[BUG] Key is 'True',Extra is 'NONE' when add rollup for DUP table (#6763)

fix #6762

The result is displayed after the repair

```
mysql> desc test2 all;
+-----------+---------------+-------+---------------+------+-------+---------+-------+---------+
| IndexName | IndexKeysType | Field | Type          | Null | Key   | Default | Extra | Visible |
+-----------+---------------+-------+---------------+------+-------+---------+-------+---------+
| test2     | DUP_KEYS      | a     | BIGINT        | Yes  | true  | NULL    |       | true    |
|           |               | b     | BIGINT        | Yes  | true  | NULL    |       | true    |
|           |               | c     | BIGINT        | Yes  | false | NULL    | NONE  | true    |
|           |               | d     | BIGINT        | Yes  | false | NULL    | NONE  | true    |
|           |               | e     | VARCHAR(1024) | Yes  | false | NULL    | NONE  | true    |
|           |               | f     | VARCHAR(1024) | Yes  | false | NULL    | NONE  | true    |
|           |               |       |               |      |       |         |       |         |
| r1        | DUP_KEYS      | c     | BIGINT        | Yes  | true  | NULL    |       | true    |
|           |               | e     | VARCHAR(1024) | Yes  | true  | NULL    |       | true    |
|           |               | a     | BIGINT        | Yes  | false | NULL    | NONE  | true    |
+-----------+---------------+-------+---------------+------+-------+---------+-------+---------+

```

fe/fe-core/src/main/java/org/apache/doris/catalog/Column.java

@@ -201,6 +201,10 @@ public class Column implements Writable {
     }
 
     public void setIsKey(boolean isKey) {
+        // column is key, aggregationType is always null, isAggregationTypeImplicit is always false.
+        if (isKey) {
+            setAggregationType(null, false);
+        }
         this.isKey = isKey;
     }
 

fe/fe-core/src/test/java/org/apache/doris/alter/RollupJobV2Test.java

@@ -426,4 +426,24 @@ public class RollupJobV2Test {
         Assert.assertEquals("to_bitmap", resultFunctionCall.getFnName().getFunction());
 
     }
+
+    @Test
+    public void testAddRollupForDupTable() throws UserException {
+        fakeCatalog = new FakeCatalog();
+        fakeEditLog = new FakeEditLog();
+        FakeCatalog.setCatalog(masterCatalog);
+        MaterializedViewHandler materializedViewHandler = Catalog.getCurrentCatalog().getRollupHandler();
+        Database db = masterCatalog.getDbOrDdlException(CatalogTestUtil.testDbId1);
+        OlapTable olapTable = (OlapTable) db.getTableOrDdlException(CatalogTestUtil.testTableId2);
+
+        AddRollupClause addRollupClause = new AddRollupClause("r1", Lists.newArrayList("k1", "v1", "v2"), null, CatalogTestUtil.testIndex2, null);
+
+        List<Column> columns = materializedViewHandler.checkAndPrepareMaterializedView(addRollupClause, olapTable, CatalogTestUtil.testIndexId2, false);
+        for (Column column : columns) {
+            if (column.nameEquals("v1", true)) {
+                Assert.assertNull(column.getAggregationType());
+                break;
+            }
+        }
+    }
 }

fe/fe-core/src/test/java/org/apache/doris/catalog/CatalogTestUtil.java

@@ -47,12 +47,23 @@ public class CatalogTestUtil {
     public static String testDb1 = "testDb1";
     public static long testDbId1 = 1;
     public static String testTable1 = "testTable1";
+    public static String testTable2 = "testTable2";
+
     public static long testTableId1 = 2;
+    public static long testTableId2 = 15;
+
     public static String testPartition1 = "testPartition1";
+    public static String testPartition2 = "testPartition2";
+
     public static long testPartitionId1 = 3;
+    public static long testPartitionId2 = 16;
+
     public static String testIndex1 = "testIndex1";
     public static String testIndex2 = "testIndex2";
+
     public static long testIndexId1 = 2; // the base indexId == tableId
+    public static long testIndexId2 = 15; // the base indexId == tableId
+
     public static int testSchemaHash1 = 93423942;
     public static long testBackendId1 = 5;
     public static long testBackendId2 = 6;
@@ -60,7 +71,11 @@ public class CatalogTestUtil {
     public static long testReplicaId1 = 8;
     public static long testReplicaId2 = 9;
     public static long testReplicaId3 = 10;
+    public static long testReplicaId4 = 17;
+
     public static long testTabletId1 = 11;
+    public static long testTabletId2 = 18;
+
     public static long testStartVersion = 12;
     public static long testStartVersionHash = 12312;
     public static long testPartitionCurrentVersionHash = 12312;
@@ -230,13 +245,62 @@ public class CatalogTestUtil {
         // add a es table to catalog
         try {
             createEsTable(db);
+            createDupTable(db);
         } catch (DdlException e) {
             // TODO Auto-generated catch block
             // e.printStackTrace();
         }
         return db;
     }
-    
+
+    public static void createDupTable(Database db) {
+
+        // replica
+        Replica replica = new Replica(testReplicaId4, testBackendId1, testStartVersion, testStartVersionHash, 0, 0L, 0L,
+                ReplicaState.NORMAL, -1, 0, 0, 0);
+
+        // tablet
+        Tablet tablet = new Tablet(testTabletId2);
+
+        // index
+        MaterializedIndex index = new MaterializedIndex(testIndexId2, IndexState.NORMAL);
+        TabletMeta tabletMeta = new TabletMeta(testDbId1, testTableId2, testPartitionId2, testIndexId2, 0, TStorageMedium.HDD);
+        index.addTablet(tablet, tabletMeta);
+
+        tablet.addReplica(replica);
+
+        // partition
+        RandomDistributionInfo distributionInfo = new RandomDistributionInfo(1);
+        Partition partition = new Partition(testPartitionId2, testPartition2, index, distributionInfo);
+        partition.updateVisibleVersionAndVersionHash(testStartVersion, testStartVersionHash);
+        partition.setNextVersion(testStartVersion + 1);
+        partition.setNextVersionHash(testPartitionNextVersionHash, testPartitionCurrentVersionHash);
+
+        // columns
+        List<Column> columns = new ArrayList<Column>();
+        Column temp = new Column("k1", PrimitiveType.INT);
+        temp.setIsKey(true);
+        columns.add(temp);
+        temp = new Column("k2", PrimitiveType.INT);
+        temp.setIsKey(true);
+        columns.add(temp);
+        columns.add(new Column("v1", ScalarType.createType(PrimitiveType.VARCHAR), false, AggregateType.NONE, "0", ""));
+        columns.add(new Column("v2", ScalarType.createType(PrimitiveType.VARCHAR), false, AggregateType.NONE, "0", ""));
+
+        // table
+        PartitionInfo partitionInfo = new SinglePartitionInfo();
+        partitionInfo.setDataProperty(testPartitionId2, DataProperty.DEFAULT_DATA_PROPERTY);
+        partitionInfo.setReplicaAllocation(testPartitionId2, new ReplicaAllocation((short) 1));
+        OlapTable table = new OlapTable(testTableId2, testTable2, columns, KeysType.DUP_KEYS, partitionInfo,
+                distributionInfo);
+        table.addPartition(partition);
+        table.setIndexMeta(testIndexId2, testIndex2, columns, 0, testSchemaHash1, (short) 3,
+                TStorageType.COLUMN, KeysType.DUP_KEYS);
+        table.setBaseIndexId(testIndexId2);
+        // db
+        db.createTable(table);
+    }
+
     public static void createEsTable(Database db) throws DdlException {
         // columns
         List<Column> columns = new ArrayList<>();