Hi,

I think it is useful to add some status counters for implicit temporary tables. The created_tmp_tables vs created_tmp_disk_tables does not always do the trick.

Can you add:

• How many bytes were written to implicit temporary tables
• How many bytes were written to implicit temporary tables on disk
• How many temporary tables on disk were created because the MEMORY storage engine did not support the schema
• How many temporary tables on disk were created because the max_tmp_table_size or max_heap_table_size was reached

Feel free to split up if some are more difficult then others, any part of this would be a significant improvement.

Thank you!
Michaël