Added metadata flag to track if stats for optimizer were loaded (#7188)

Author: pavelvelikhov

ydb/core/kqp/gateway/kqp_metadata_loader.cpp

@@ -891,6 +891,7 @@ NThreading::TFuture<TTableMetadataResult> TKqpTableMetadataLoader::LoadTableMeta
                     auto s = std::get<NKikimr::NStat::TStatSimple>(resp.Statistics);
                     result.Metadata->RecordsCount = s.RowCount;
                     result.Metadata->DataSize = s.BytesSize;
+                    result.Metadata->StatsLoaded = true;
                 }
                 promise.SetValue(result);
         });

ydb/core/kqp/provider/yql_kikimr_gateway.h

@@ -416,6 +416,7 @@ struct TKikimrTableMetadata : public TThrRefBase {
     ui64 DataSize = 0;
     ui64 MemorySize = 0;
     ui32 ShardsCount = 0;
+    bool StatsLoaded = false;
 
     TInstant LastAccessTime;
     TInstant LastUpdateTime;
@@ -452,6 +453,7 @@ struct TKikimrTableMetadata : public TThrRefBase {
         , Kind(static_cast<EKikimrTableKind>(message->GetKind()))
         , RecordsCount(message->GetRecordsCount())
         , DataSize(message->GetDataSize())
+        , StatsLoaded(message->GetStatsLoaded())
         , KeyColumnNames(message->GetKeyColunmNames().begin(), message->GetKeyColunmNames().end())
 
     {
@@ -519,6 +521,7 @@ struct TKikimrTableMetadata : public TThrRefBase {
         message->SetKind(static_cast<ui32>(Kind));
         message->SetRecordsCount(RecordsCount);
         message->SetDataSize(DataSize);
+        message->SetStatsLoaded(StatsLoaded);
         for(auto& [key, value] : Attributes) {
             message->AddAttributes()->SetKey(key);
             message->AddAttributes()->SetValue(value);

ydb/core/protos/kqp.proto

@@ -169,6 +169,7 @@ message TKqpTableMetadataProto {
     repeated TKqpTableMetadataProto SecondaryGlobalIndexMetadata = 12;
     optional uint64 RecordsCount = 13;
     optional uint64 DataSize = 14;
+    optional bool StatsLoaded = 15;
 }
 
 message TRlPath {