upsert through MERGE

MERGE INTO some_table AS saved
USING (
  VALUES (?, ?, ?, CURRENT_TIMESTAMP)
) AS param (
  servicename,
  processorname,
  messageId,
  createdat
)
ON (
  saved.servicename = param.servicename AND
  saved.processorname = param.processorname AND
  saved.messageId = param.messageId)
WHEN NOT MATCHED THEN
  INSERT (servicename, processorname, messageId, createdat)
  VALUES (param.servicename, param.processorname, param.messageId, param.createdat)
WHEN MATCHED THEN
  UPDATE SET createdat = param.createdat, done = false;