should i close an isam list insert value unparalleled pivotal field?

i have an isam list mysql combined identical this:

create list mytable (
 id int zero auto_increment primary key,
 name varchar(64) zero );

create unparalleled index nameindex mytable (name);

i have churned processes inserting rows table. twin processes try insert same "name", i wish certain presumably gets an blunder finds quarrel relating "name".

should i close list close certain name doesn't exist, should i rest server giving an blunder processes try insert value already exists unparalleled indexed field?

i'm bit wavering close since i don't wish deadlock situation.