diff --git a/db/db_info_dumper.cc b/db/db_info_dumper.cc
index 2c38655fc..55c8bb95a 100644
--- a/db/db_info_dumper.cc
+++ b/db/db_info_dumper.cc
@@ -64,9 +64,10 @@ void DumpDBFileSummary(const ImmutableDBOptions& options,
         break;
       case kWalFile:
         if (env->GetFileSize(dbname + "/" + file, &file_size).ok()) {
-          char str[16];
-          snprintf(str, sizeof(str), "%" PRIu64, file_size);
-          wal_info.append(file).append(" size: ").append(str).append(" ; ");
+          wal_info.append(file)
+              .append(" size: ")
+              .append(std::to_string(file_size))
+              .append(" ; ");
         } else {
           Error(options.info_log, "Error when reading LOG file: %s/%s\n",
                 dbname.c_str(), file.c_str());
@@ -120,9 +121,10 @@ void DumpDBFileSummary(const ImmutableDBOptions& options,
       if (ParseFileName(file, &number, &type)) {
         if (type == kWalFile) {
           if (env->GetFileSize(options.wal_dir + "/" + file, &file_size).ok()) {
-            char str[16];
-            snprintf(str, sizeof(str), "%" PRIu64, file_size);
-            wal_info.append(file).append(" size: ").append(str).append(" ; ");
+            wal_info.append(file)
+                .append(" size: ")
+                .append(std::to_string(file_size))
+                .append(" ; ");
           } else {
             Error(options.info_log, "Error when reading LOG file %s/%s\n",
                   options.wal_dir.c_str(), file.c_str());