Restore shouldIndex of ModelColumn

Signed-off-by: NGao Hongtao <hanahmily@gmail.com>

oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/storage/model/ModelColumn.java

@@ -104,9 +104,6 @@ public class ModelColumn {
      * @return true means this column should be indexed, as it would be a query condition.
      */
     public boolean shouldIndex() {
-        if (banyanDBExtension != null) {
-            return banyanDBExtension.shouldIndex();
-        }
         return !storageOnly;
     }
 }

oap-server/server-storage-plugin/storage-banyandb-plugin/src/main/java/org/apache/skywalking/oap/server/storage/plugin/banyandb/MetadataRegistry.java

@@ -309,7 +309,7 @@ public enum MetadataRegistry {
             final TagFamilySpec.TagSpec tagSpec = parseTagSpec(col);
             builder.spec(columnStorageName, new ColumnSpec(ColumnType.TAG, col.getType()));
             String colName = col.getColumnName().getStorageName();
-            if (!shardingColumns.contains(colName) && col.shouldIndex()) {
+            if (!shardingColumns.contains(colName) && col.getBanyanDBExtension().shouldIndex()) {
                 // build indexRule
                 IndexRule indexRule = parseIndexRule(tagSpec.getTagName(), col);
                 tagMetadataList.add(new TagMetadata(indexRule, tagSpec));
@@ -354,7 +354,7 @@ public enum MetadataRegistry {
             final TagFamilySpec.TagSpec tagSpec = parseTagSpec(col);
             builder.spec(columnStorageName, new ColumnSpec(ColumnType.TAG, col.getType()));
             String colName = col.getColumnName().getStorageName();
-            result.tag(new TagMetadata(!shardingColumns.contains(colName) && col.shouldIndex() ? parseIndexRule(tagSpec.getTagName(), col) : null, tagSpec));
+            result.tag(new TagMetadata(!shardingColumns.contains(colName) && col.getBanyanDBExtension().shouldIndex() ? parseIndexRule(tagSpec.getTagName(), col) : null, tagSpec));
         }
 
         return result.build();