Set field Engine to 1 to maintain backward compatibility (#15878)

Author: aavdonkin

ydb/core/protos/flat_scheme_op.proto

@@ -566,6 +566,7 @@ message TColumnTableSchema {
     repeated TOlapColumnDescription Columns = 1;
     repeated string KeyColumnNames = 2;
 
+    optional EColumnTableEngine Engine = 3;
     // Internal fields
     optional uint32 NextColumnId = 4;
 

ydb/core/tx/columnshard/tables_manager.cpp

@@ -276,6 +276,7 @@ void TTablesManager::AddSchemaVersion(
         it->second = schema;
     }
 
+    versionInfo.MutableSchema()->SetEngine(NKikimrSchemeOp::COLUMN_ENGINE_REPLACING_TIMESERIES);
     Schema::SaveSchemaPresetVersionInfo(db, presetId, version, versionInfo);
     if (!PrimaryIndex) {
         PrimaryIndex = std::make_unique<NOlap::TColumnEngineForLogs>(TabletId, SchemaObjectsCache, DataAccessorsManager, StoragesManager,

ydb/core/tx/schemeshard/schemeshard_impl.cpp

@@ -3649,8 +3649,12 @@ void TSchemeShard::PersistColumnTable(NIceDb::TNiceDb& db, TPathId pathId, const
 
     TString serialized;
     TString serializedSharding;
-    Y_ABORT_UNLESS(tableInfo.Description.SerializeToString(&serialized));
-    Y_ABORT_UNLESS(tableInfo.Description.GetSharding().SerializeToString(&serializedSharding));
+    auto tableInfoCopy = tableInfo;
+    if (tableInfo.IsStandalone()) {
+        tableInfoCopy.Description.MutableSchema()->SetEngine(NKikimrSchemeOp::COLUMN_ENGINE_REPLACING_TIMESERIES);
+    }
+    Y_ABORT_UNLESS(tableInfoCopy.Description.SerializeToString(&serialized));
+    Y_ABORT_UNLESS(tableInfoCopy.Description.GetSharding().SerializeToString(&serializedSharding));
 
     if (isAlter) {
         db.Table<Schema::ColumnTablesAlters>().Key(pathId.LocalPathId).Update(