What are the factors used to determine whether to grant a short trial continuance due to the unavailability of a witness?

["While the unavailability of a witness is considered good cause for a continuance . . . , the unavailability must be combined with the fact the witness has been subpoenaed (or is beyond the reach of a subpoena and has agreed to be present), and the witness's absence is 'an unavoidable emergency that counsel did not know and could not reasonably have known at the time of the pretrial or trial setting conference.' [Citations.]"]; cf. Jurado v. Toys "R" Us, Inc. (1993) 12 Cal.App.4th 1615, 1618 [request for short trial continuance should have been granted due to unavailability of non-party witnesses where plaintiff's counsel "exercised due diligence" by promptly serving witnesses with subpoenas and following up on them, but where witnesses failed to respect the subpoenas].)

III. Additional Factors for Determining Whether to Grant Continuance