California Code, Code of Civil Procedure - CCP § 1986.5

Any person who is subpoenaed and required to give a deposition shall be entitled to receive the same witness fees and mileage as if the subpoena required him or her to attend and testify before a court in which the action or proceeding is pending.Notwithstanding this requirement, the only fees owed to a witness who is required to produce business records under Section 1560 of the Evidence Code pursuant to a subpoena duces tecum, but who is not required to personally attend a deposition away from his or her place of business, shall be those prescribed in Section 1563 of the Evidence Code.