I have just become aware of this particular Article 29, which has one good side: it is short.
The processor and any person acting under the authority of the controller or of the processor, who has access to personal data, shall not process those data except on instructions from the controller, unless required to do so by Union or Member State law.
Then in Article 28 about "Processor",
(a) processes the personal data only on documented instructions from the controller, including with regard to transfers of personal data to a third country or an international organisation, unless required to do so by Union or Member State law to which the processor is subject; in such a case, the processor shall inform the controller of that legal requirement before processing, unless that law prohibits such information on important grounds of public interest;
Not to mention Article 32.
If I were to be asked about any instructions, "I don't know" kind of answer would probably be the only one. I have mostly developed new features for a MVC framework and installed those new features to the production system. Things like checklists and guidelines have not been provided.
Right now my own conclusion is that I should not to copy or modify any database or install any code update that changes how personal data is processed.
I have been employed on a small company for some years, i.e. before and after gdpr come to effect. The company acts as a processor for multiple controllers.
I'll probably make some phone calls anyway tomorrow.