A few days ago, when executing DROP TABLE in MySQL, all processes including DDL and DML were hung until DROP TABLE was completed. I am confused about this phenomenon.I have reviewed the source codes of MySQL to check how MySQL internally handle DROP TABLE.When user trigger DROP TABLE command:########################MySQL SERVER drop table########################/* Sql_table.cc  delete (drop) tables. */bool mysql_rm_table( )  /*   Execute the drop of a normal or temporary table */  int mysql_rm_table_part2 ()    /* Remove matching tables from the HANDLER&...