út 20. 4. 2021 v 4:47 odesílatel Andy Fan <zhihui.fan1...@gmail.com> napsal:
> > > > - a PL/PGSQL function's meaning depends on the search path in effect > when it is called, unless it has a SET search_path clause or it fully > qualifies all object references, so it isn't actually possible in general > to determine what a function calls at definition time > > > I'd think this one as a blocker issue at the beginning since I have to > insist on > any new features should not cause semantic changes for existing ones. > Later I > found the new definition. As for this feature request, I think we can > define the > features like this: > > 1. We define a new attribute named VOLATILE_AUTO; The semantic is PG will > auto > detect the volatile info based on current search_path / existing > function. If any embedded function can't be found, we can raise an > error if > VOLATILE_AUTO is used. If people change the volatile attribute later, > we can: > a). do nothing. This can be the documented feature. or. b). Maintain the > dependency tree between functions and if anyone is changed, other > functions > should be recalculated as well. > > 2. VOLATILE_AUTO should never be the default value. It only works when > people > requires it. > > Then what we can get from this? Thinking a user is migrating lots of UDF > from > other databases. Asking them to check/set each function's attribute might > be bad. However if we tell them about how VOLATILE_AUTO works, and they > accept it (I guess most people would accept), then the migration would be > pretty productive. > > I'm listening to any obvious reason to reject it. > a) This analyses can be very slow - PLpgSQL does lazy planning - query plans are planned only when are required - and this feature requires complete planning current function and all nested VOLATILE_AUTO functions - so start of function can be significantly slower b) When you migrate from Oracle,then you can use the STABLE flag, and it will be mostly correct. Regards Pavel > -- > Best Regards > Andy Fan (https://www.aliyun.com/) >
