Hi Henson, > rest. So evaluating its DEFINE -- option (b) -- would mean running a clause > the standard tells us to ignore.
Right. > Agreed, and the parallel is convincing. An unused window already escapes > the negative-frame-offset check, so singling out DEFINE as the one clause > that must fire regardless would be inconsistent with how the rest of an > unused window already behaves. > > This also matches the planner: select_active_windows() drops any window with > no referencing WindowFunc, and its comment already cites the same <window > clause> General Rules (General Rule 4) as its basis. > > Either way, the disregard rule governs only execution. A failure raised in > the parser, transform, rewrite, or planner is a separate, static layer the > rule does not touch. And at execution there is nothing to evaluate: an > unused window is never turned into a WindowAgg node, so its DEFINE is never > reached. Yes, the rule only applies to execution. I think what we do in other phases is implementation dependent. > So I'm convinced -- let's keep (a), the current behavior, and I'll treat > this open question as closed, with no patch change. For the record, the two > halves stay cleanly separated: the RPR DEFINE volatility check still visits > every window clause at preprocessing (independent of select_active_windows), > while run-time DEFINE evaluation happens only for windows that survive it. > > Thanks for digging up the standard text. You are welcome. Please feel free to ask me if you want to know what 9075-2 says about someting. Regards, -- Tatsuo Ishii SRA OSS K.K. English: http://www.sraoss.co.jp/index_en/ Japanese:http://www.sraoss.co.jp
