Fix subcolumns problems (#28200)

Author: Vladilen

ydb/core/formats/arrow/accessor/sub_columns/accessor.cpp

@@ -138,10 +138,6 @@ class TJsonRestorer {
         bool enqueue = false;
         bool wasEnqueue = false;
         NJson::TJsonValue* current = &Result;
-        if (path.empty()) {
-            current->InsertValue(path, jsonValue);
-            return;
-        }
         for (ui32 i = 0; i < path.size(); ++i) {
             if (path[i] == '\\') {
                 ++i;
@@ -195,7 +191,7 @@ class TJsonRestorer {
             TStringBuf key(path.data() + start + 1, (path.size() - 1) - start - 1);
             current->InsertValue(key, jsonValue);
         } else {
-            AFL_VERIFY(path.size() > start)("path", path)("start", start);
+            AFL_VERIFY(path.size() >= start)("path", path)("start", start);
             TStringBuf key(path.data() + start, (path.size()) - start);
             ui32 keyIndex;
             if (key.StartsWith("[") && key.EndsWith("]") && TryFromString<ui32>(key.data() + 1, key.size() - 2, keyIndex)) {

ydb/core/tx/columnshard/engines/scheme/indexes/abstract/fetcher.cpp

@@ -47,6 +47,7 @@ void TIndexFetcherLogic::DoOnDataReceived(TReadActionsCollection& nextRead, NBlo
             ranges.insert(ranges.end(), rangesLocal.begin(), rangesLocal.end());
         }
     }
+    std::sort(ranges.begin(), ranges.end());
     ranges.erase(std::unique(ranges.begin(), ranges.end()), ranges.end());
     if (ranges.size()) {
         auto reading = blobsAction.GetReading(StorageId);