hopefully the last case of walk-and-delete HASH antipattern

here global_index_stats is expected to be big, so we don't
restart the search, but use a two-pass approach

sql/handler.cc

@@ -7233,11 +7233,13 @@ static
 int del_global_index_stats_for_table(THD *thd, uchar* cache_key, size_t cache_key_length)
 {
   int res = 0;
+  uint to_delete_counter= 0;
+  INDEX_STATS *index_stats_to_delete[MAX_INDEXES];
   DBUG_ENTER("del_global_index_stats_for_table");
 
   mysql_mutex_lock(&LOCK_global_index_stats);
 
-  for (uint i= 0; i < global_index_stats.records;)
+  for (uint i= 0; i < global_index_stats.records; i++)
   {
     INDEX_STATS *index_stats =
       (INDEX_STATS*) my_hash_element(&global_index_stats, i);
@@ -7247,19 +7249,13 @@ int del_global_index_stats_for_table(THD *thd, uchar* cache_key, size_t cache_ke
 	index_stats->index_name_length >= cache_key_length &&
 	!memcmp(index_stats->index, cache_key, cache_key_length))
     {
-      res= my_hash_delete(&global_index_stats, (uchar*)index_stats);
-      /*
-          In our HASH implementation on deletion one elements
-          is moved into a place where a deleted element was,
-          and the last element is moved into the empty space.
-          Thus we need to re-examine the current element, but
-          we don't have to restart the search from the beginning.
-      */
+      index_stats_to_delete[to_delete_counter++]= index_stats;
     }
-    else
-      i++;
   }
 
+  for (uint i= 0; i < to_delete_counter; i++)
+    res= my_hash_delete(&global_index_stats, (uchar*)index_stats_to_delete[i]);
+
   mysql_mutex_unlock(&LOCK_global_index_stats);
   DBUG_RETURN(res);
 }