diff --git a/src/Storages/MergeTree/MergeTreeMarksLoader.cpp b/src/Storages/MergeTree/MergeTreeMarksLoader.cpp
index 9a5576f0ad2..5c722eec380 100644
--- a/src/Storages/MergeTree/MergeTreeMarksLoader.cpp
+++ b/src/Storages/MergeTree/MergeTreeMarksLoader.cpp
@@ -135,6 +135,7 @@ MarkCache::MappedPtr MergeTreeMarksLoader::loadMarksImpl()
     if (!index_granularity_info.mark_type.adaptive)
     {
         /// Read directly to marks.
+        chassert(expected_uncompressed_size == plain_marks.size() * sizeof(MarkInCompressedFile));
         reader->readStrict(reinterpret_cast<char *>(plain_marks.data()), expected_uncompressed_size);
 
         if (!reader->eof())
@@ -148,23 +149,25 @@ MarkCache::MappedPtr MergeTreeMarksLoader::loadMarksImpl()
     }
     else
     {
-        size_t i = 0;
-        size_t granularity;
-        while (!reader->eof())
+        for (size_t i = 0; i < marks_count; ++i)
         {
+            if (reader->eof())
+                throw Exception(
+                    ErrorCodes::CANNOT_READ_ALL_DATA,
+                    "Cannot read all marks from file {}, marks expected {} (bytes size {}), marks read {} (bytes size {})",
+                    mrk_path, marks_count, expected_uncompressed_size, i, reader->count());
+
+            size_t granularity;
             reader->readStrict(
                 reinterpret_cast<char *>(plain_marks.data() + i * columns_in_mark), columns_in_mark * sizeof(MarkInCompressedFile));
             readIntBinary(granularity, *reader);
-            ++i;
         }
 
-        if (i * mark_size != expected_uncompressed_size)
-        {
+        if (!reader->eof())
             throw Exception(
                 ErrorCodes::CANNOT_READ_ALL_DATA,
-                "Cannot read all marks from file {}, marks expected {} (bytes size {}), marks read {} (bytes size {})",
-                mrk_path, marks_count, expected_uncompressed_size, i, reader->count());
-        }
+                "Too many marks in file {}, marks expected {} (bytes size {})",
+                mrk_path, marks_count, expected_uncompressed_size);
     }
 
     auto res = std::make_shared<MarksInCompressedFile>(plain_marks);