diff --git a/db/db_impl.cc b/db/db_impl.cc
index 5a4a0ab60..923abd5db 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -948,8 +948,8 @@ Status DBImpl::DoCompactionWork(CompactionState* compact) {
       compact->compaction->level(),
       compact->compaction->num_input_files(1),
       compact->compaction->level() + 1);
-  char scratch[200];
-  compact->compaction->Summary(scratch, 256);
+  char scratch[256];
+  compact->compaction->Summary(scratch, sizeof(scratch));
   Log(options_.info_log, "Compaction start summary: %s\n", scratch);
 
   assert(versions_->NumLevelFiles(compact->compaction->level()) > 0);
diff --git a/db/version_set.cc b/db/version_set.cc
index 1fcf831c8..141036536 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -1620,10 +1620,10 @@ void Compaction::Summary(char* output, int len) {
     return;
 
   char level_low_summary[100];
-  InputSummary(inputs_[0], level_low_summary, 100);
+  InputSummary(inputs_[0], level_low_summary, sizeof(level_low_summary));
   char level_up_summary[100];
   if (inputs_[1].size()) {
-    InputSummary(inputs_[1], level_up_summary, 100);
+    InputSummary(inputs_[1], level_up_summary, sizeof(level_up_summary));
   } else {
     level_up_summary[0] = '\0';
   }