1set default_storage_engine='tokudb'; 2drop table if exists tt; 3create table tt (a int, b int, c int, key(b), key(c), primary key(a)); 4insert into tt values (1,0,0),(2,0,0),(3,0,1),(4,0,1); 5show indexes from tt; 6Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment 7tt 0 PRIMARY 1 a A 4 NULL NULL BTREE 8tt 1 b 1 b A 4 NULL NULL YES BTREE 9tt 1 c 1 c A 4 NULL NULL YES BTREE 10analyze table tt; 11Table Op Msg_type Msg_text 12test.tt analyze status OK 13show indexes from tt; 14Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment 15tt 0 PRIMARY 1 a A 4 NULL NULL BTREE 16tt 1 b 1 b A 2 NULL NULL YES BTREE 17tt 1 c 1 c A 4 NULL NULL YES BTREE 18alter table tt drop primary key; 19show indexes from tt; 20Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment 21tt 1 b 1 b A 4 NULL NULL YES BTREE 22tt 1 c 1 c A 4 NULL NULL YES BTREE 23flush tables; 24show indexes from tt; 25Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment 26tt 1 b 1 b A 4 NULL NULL YES BTREE 27tt 1 c 1 c A 4 NULL NULL YES BTREE 28drop table tt; 29