diff --git a/repair/row_level.cc b/repair/row_level.cc
index c79865cd3f..0db0a80221 100644
--- a/repair/row_level.cc
+++ b/repair/row_level.cc
@@ -956,7 +956,7 @@ private:
         return repair_hash(h.finalize_uint64());
     }
 
-    stop_iteration handle_mutation_fragment(mutation_fragment_opt mfopt, size_t& cur_size, std::list<repair_row>& cur_rows) {
+    stop_iteration handle_mutation_fragment(mutation_fragment_opt mfopt, size_t& cur_size, size_t& new_rows_size, std::list<repair_row>& cur_rows) {
         if (!mfopt) {
             return stop_iteration::yes;
         }
@@ -978,6 +978,7 @@ private:
         _metrics.row_from_disk_nr++;
         _metrics.row_from_disk_bytes += r.size();
         cur_size += r.size();
+        new_rows_size += r.size();
         cur_rows.push_back(std::move(r));
         return stop_iteration::no;
     }
@@ -985,19 +986,19 @@ private:
     // Read rows from sstable until the size of rows exceeds _max_row_buf_size  - current_size
     // This reads rows from where the reader left last time into _row_buf
     // _current_sync_boundary or _last_sync_boundary have no effect on the reader neither.
-    future<std::list<repair_row>>
+    future<std::list<repair_row>, size_t>
     read_rows_from_disk(size_t cur_size) {
-        return do_with(cur_size, std::list<repair_row>(), [this] (size_t& cur_size, std::list<repair_row>& cur_rows) {
-            return repeat([this, &cur_size, &cur_rows] () mutable {
+        return do_with(cur_size, size_t(0), std::list<repair_row>(), [this] (size_t& cur_size, size_t& new_rows_size, std::list<repair_row>& cur_rows) {
+            return repeat([this, &cur_size, &cur_rows, &new_rows_size] () mutable {
                 if (cur_size >= _max_row_buf_size) {
                     return make_ready_future<stop_iteration>(stop_iteration::yes);
                 }
                 _gate.check();
-                return _repair_reader.read_mutation_fragment().then([this, &cur_size, &cur_rows] (mutation_fragment_opt mfopt) mutable {
-                    return handle_mutation_fragment(std::move(mfopt), cur_size, cur_rows);
+                return _repair_reader.read_mutation_fragment().then([this, &cur_size, &new_rows_size, &cur_rows] (mutation_fragment_opt mfopt) mutable {
+                    return handle_mutation_fragment(std::move(mfopt), cur_size, new_rows_size, cur_rows);
                 });
-            }).then([&cur_rows] () mutable {
-                return std::move(cur_rows);
+            }).then([&cur_rows, &new_rows_size] () mutable {
+                return make_ready_future<std::list<repair_row>, size_t>(std::move(cur_rows), new_rows_size);
             });
         });
     }
@@ -1020,8 +1021,7 @@ private:
         rlogger.trace("SET _last_sync_boundary from {} to {}", _last_sync_boundary, _current_sync_boundary);
         _last_sync_boundary = _current_sync_boundary;
         size_t current_size = row_buf_size();
-        return read_rows_from_disk(current_size).then([this, skipped_sync_boundary = std::move(skipped_sync_boundary)] (std::list<repair_row> new_rows) mutable {
-            size_t new_rows_size = get_repair_rows_size(new_rows);
+        return read_rows_from_disk(current_size).then([this, skipped_sync_boundary = std::move(skipped_sync_boundary)] (std::list<repair_row> new_rows, size_t new_rows_size) mutable {
             size_t new_rows_nr = new_rows.size();
             _row_buf.splice(_row_buf.end(), new_rows);
             return row_buf_csum().then([this, new_rows_size, new_rows_nr, skipped_sync_boundary = std::move(skipped_sync_boundary)] (repair_hash row_buf_combined_hash) {