1 files changed, 5 insertions, 0 deletions
diff --git a/mysys/tree.c b/mysys/tree.c
index 91d2f9771b5..42c58131100 100644
--- a/mysys/tree.c
+++ b/mysys/tree.c
@@ -109,6 +109,11 @@ void init_tree(TREE *tree, uint default_alloc_size, uint memory_limit,
   if (!free_element && size >= 0 &&
       ((uint) size <= sizeof(void*) || ((uint) size & (sizeof(void*)-1))))
   {
+    /*
+      We know that the data doesn't have to be aligned (like if the key
+      contains a double), so we can store the data combined with the
+      TREE_ELEMENT.
+    */
     tree->offset_to_key=sizeof(TREE_ELEMENT); /* Put key after element */
     /* Fix allocation size so that we don't lose any memory */
     default_alloc_size/=(sizeof(TREE_ELEMENT)+size);