ORA-01450: maximum key length (‥) exceeded

Demonstration

create table tq84_ora_01450(
   id   number,
   v1   varchar2(4000),
   v2   varchar2(2394)
);

create index tq84_ora_01450_ix on tq84_ora_01450(v1, v2);
-- ORA-01450: maximum key length (6397) exceeded

alter table tq84_ora_01450 modify v2 varchar2(2393);
create index tq84_ora_01450_ix on tq84_ora_01450(v1, v2);
-- Index TQ84_ORA_01450_IX created.

drop table tq84_ora_01450;

See also