View Mysql index page fragments

Query index page fragments: show table status like 'table name'; // when the value of the Data_free column is greater than 0, fragments are generated (as long as data is deleted, the premise is to create an index) OPTIMIZE the TABLE: optimize table name; create an index condition (OR): The TABLE has a large amount of data (if the data size is small, the index creation effect is not obvious, but it wastes physical space, increase the difficulty of table maintenance) primary key column/foreign key column (accelerate join)/common search column view database encoding: show variables like 'character _ set % '; set the return result encoding: SET character_set_results = UTF-8; prepared by 897457487