1 files changed, 5 insertions, 0 deletions
diff --git a/src/coins.h b/src/coins.h
index b1a2c08845..902cb57f69 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -269,6 +269,11 @@ struct CCoinsCacheEntry
     enum Flags {
         DIRTY = (1 << 0), // This cache entry is potentially different from the version in the parent view.
         FRESH = (1 << 1), // The parent view does not have this entry (or it is pruned).
+        /* Note that FRESH is a performance optimization with which we can
+         * erase coins that are fully spent if we know we do not need to
+         * flush the changes to the parent cache.  It is always safe to
+         * not mark FRESH if that condition is not guaranteed.
+         */
     };
 
     CCoinsCacheEntry() : coins(), flags(0) {}