MDEV-5675 - Performance: my_hash_sort_bin is called too often

Reduced number of my_hash_sort_bin() calls from 4 to 1 per query.
Reduced number of memory accesses done by my_hash_sort_bin().

Details:
- let MDL subsystem use pre-calculated hash value for hash
  inserts and deletes
- let table cache use pre-calculated MDL hash value
- MDL namespace is excluded from hash value calculation, so that
  hash value can be used by table cache as is
- hash value for MDL is calculated as resulting hash value + MDL
  namespace
- extended hash implementation to accept user defined hash function

1 files changed, 1 insertions, 1 deletions

diff --git a/client/mysqltest.cc b/client/mysqltest.cc
index d6158f471fd..3304af3981d 100644
--- a/client/mysqltest.cc
+++ b/client/mysqltest.cc
@@ -8945,7 +8945,7 @@ int main(int argc, char **argv)
   my_init_dynamic_array(&q_lines, sizeof(struct st_command*), 1024, 1024, MYF(0));
 
   if (my_hash_init2(&var_hash, 64, charset_info,
-                 128, 0, 0, get_var_key, var_free, MYF(0)))
+                 128, 0, 0, get_var_key, 0, var_free, MYF(0)))
     die("Variable hash initialization failed");
 
   var_set_string("MYSQL_SERVER_VERSION", MYSQL_SERVER_VERSION);