First of all, if you don't have any conditions on which rows to delete, you could just truncate the table.
TRUNCATE TABLE table_1;
TRUNCATE
is a ddl operation and it does not phsically delete the rows, it only manipulates the high water mark, making the operations very fast. But also keep in mind that it cannot be rolled back, since it is DDL.
On the other hand, you can perform a direct path insert, instead of the regular one. Try this:
INSERT /*+ append */ into table_1 select * from view_1;
This will cause Oracle to write the data directly above high watermark, making the operation faster. It will also probably help if your tables are PARALLEL
.