Oregon Revised Statutes Procedure in Criminal Matters Generally § 136.567

(1) A defendant in a criminal action is entitled, at the expense of the state or city, to have subpoenas issued for not to exceed 10 witnesses within the state. A defendant is entitled, at the expense of the defendant, to have subpoenas issued for any number of additional witnesses without an order of the court. The defendant is responsible for the costs of serving the subpoenas and for the costs, as provided in ORS 136.602, of witness per diem and mileage and for expenses allowed under ORS 136.603.

(2) Any subpoena that a defendant in a criminal action is entitled to have issued shall be issued:

(3) A prosecution for violation of ORS 813.010 may not be dismissed based solely on the unavailability of a witness who was subpoenaed by the defendant to provide testimony with respect to an instrument that was used to test a person's breath, blood or urine to determine the alcoholic content of the person's blood. This subsection does not apply to the subpoena of an officer or employee of a public body, as defined in ORS 174.109.