BUG#18160 - Memory-/HEAP Table endless growing indexes

Updating data in HEAP table with BTREE index results in wrong index_length
counter value, which keeps growing after each update.

When inserting new record into tree counter is incremented by:
sizeof(TREE_ELEMENT) + key_size + tree->size_of_element
But when deleting element from tree it doesn't decrement counter by key_size:
sizeof(TREE_ELEMENT) + tree->size_of_element

This fix makes accurate allocated memory counter for tree. That is
decrease counter by key_size when deleting tree element.

heap/hp_delete.c

@@ -79,7 +79,8 @@ int hp_rb_delete_key(HP_INFO *info, register HP_KEYDEF *keyinfo,
   custom_arg.key_length= hp_rb_make_key(keyinfo, info->recbuf, record, recpos);
   custom_arg.search_flag= SEARCH_SAME;
   old_allocated= keyinfo->rb_tree.allocated;
-  res= tree_delete(&keyinfo->rb_tree, info->recbuf, &custom_arg);
+  res= tree_delete(&keyinfo->rb_tree, info->recbuf, custom_arg.key_length,
+                   &custom_arg);
   info->s->index_length-= (old_allocated - keyinfo->rb_tree.allocated);
   return res;
 }

include/my_tree.h

@@ -84,7 +84,7 @@ TREE_ELEMENT *tree_insert(TREE *tree,void *key, uint key_size,
 void *tree_search(TREE *tree, void *key, void *custom_arg);
 int tree_walk(TREE *tree,tree_walk_action action,
 	      void *argument, TREE_WALK visit);
-int tree_delete(TREE *tree, void *key, void *custom_arg);
+int tree_delete(TREE *tree, void *key, uint key_size, void *custom_arg);
 void *tree_search_key(TREE *tree, const void *key, 
                       TREE_ELEMENT **parents, TREE_ELEMENT ***last_pos,
                       enum ha_rkey_function flag, void *custom_arg);

myisam/myisamlog.c

@@ -475,7 +475,7 @@ static int examine_log(my_string file_name, char **table_names)
       {
 	if (!curr_file_info->closed)
 	  files_open--;
-	VOID(tree_delete(&tree, (gptr) curr_file_info, tree.custom_arg));
+        VOID(tree_delete(&tree, (gptr) curr_file_info, 0, tree.custom_arg));
       }
       break;
     case MI_LOG_EXTRA:

mysql-test/r/heap_btree.result

@@ -246,3 +246,13 @@ DELETE from t1 where a < 100;
 SELECT * from t1;
 a
 DROP TABLE t1;
+CREATE TABLE t1(val INT, KEY USING BTREE(val)) ENGINE=memory;
+INSERT INTO t1 VALUES(0);
+SELECT INDEX_LENGTH FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME='t1';
+INDEX_LENGTH
+21
+UPDATE t1 SET val=1;
+SELECT INDEX_LENGTH FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME='t1';
+INDEX_LENGTH
+21
+DROP TABLE t1;

mysql-test/t/heap_btree.test

@@ -164,4 +164,14 @@ DELETE from t1 where a < 100;
 SELECT * from t1;
 DROP TABLE t1;
 
+#
+# BUG#18160 - Memory-/HEAP Table endless growing indexes
+#
+CREATE TABLE t1(val INT, KEY USING BTREE(val)) ENGINE=memory;
+INSERT INTO t1 VALUES(0);
+SELECT INDEX_LENGTH FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME='t1';
+UPDATE t1 SET val=1;
+SELECT INDEX_LENGTH FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA=DATABASE() AND TABLE_NAME='t1';
+DROP TABLE t1;
+
 # End of 4.1 tests

mysys/tree.c

@@ -271,7 +271,7 @@ TREE_ELEMENT *tree_insert(TREE *tree, void *key, uint key_size,
   return element;
 }
 
-int tree_delete(TREE *tree, void *key, void *custom_arg)
+int tree_delete(TREE *tree, void *key, uint key_size, void *custom_arg)
 {
   int cmp,remove_colour;
   TREE_ELEMENT *element,***parent, ***org_parent, *nod;
@@ -326,8 +326,7 @@ int tree_delete(TREE *tree, void *key, void *custom_arg)
     rb_delete_fixup(tree,parent);
   if (tree->free)
     (*tree->free)(ELEMENT_KEY(tree,element), free_free, tree->custom_arg);
-  /* This doesn't include key_size, but better than nothing */
-  tree->allocated-= sizeof(TREE_ELEMENT)+tree->size_of_element;
+  tree->allocated-= sizeof(TREE_ELEMENT) + tree->size_of_element + key_size;
   my_free((gptr) element,MYF(0));
   tree->elements_in_tree--;
   return 0;