UDF are usable in UPDATE statement as actually trying them shows, it's just the documented grammar that needs fixing.
But as far as doing something like: UPDATE test_table SET data=max_int(data,5) WHERE idx='abc’; this is indeed *not* supported and likely never will. One big pillar of C* design is that normal writes like this don't do a read-before-write, both for performance and because of consistency constraints, so we can't have update depend on the previous value in any way. I'll note that maybe that make UDF useless for you and if so, I'm sorry, but you just can't use UDF in C* for that and you'd have to do a manual read-before-write client side to achieve this. For the sake of avoiding confusion, I will not that we do allow: UPDATE test_table SET c = c + 1 WHERE idx='abc'; if c is a counter, but that's a very special case. Counters have a completely separate path and implementation and do have a read-before-write (and are slower than normal update as a result). On Thu, Mar 10, 2016 at 11:11 PM, Kim Liu <k...@edgewaternetworks.com> wrote: > It does sounds like the use of UDF in UPDATE is in an ambiguous state at > the moment, then. The document grammar says they can’t be used, but the > document examples say they can, and the server will execute them, but it > can’t execute them in a useful way (i.e. no row supplied data.) > > So essentially not useable at the moment, regardless of intent. > > Thanks, > —Kim > > From: DuyHai Doan <doanduy...@gmail.com> > Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org> > Date: Thursday, March 10, 2016 at 14:03 > To: "user@cassandra.apache.org" <user@cassandra.apache.org> > Subject: Re: Using User Defined Functions in UPDATE queries > > Surely an error because the grammar definition for UPDATE does not mention > any function call: > [SNIPPED] > > Unless the grammar in the doc is itself not up-to-date.... > >> >>>
