Re: Request for Patch Feedback: Lag & Lead Window Functions Can Ignore Nulls

> this should throw a FEATURE_NOT_SUPPORTED error if it is used for window
functions that don't support it
> arbitrary aggregate functions over a window ... should also throw a
FEATURE_NOT_SUPPORTED error.

Fixed (with test cases) in the attached patch.

> because the same window may be shared by multiple window function calls.

Ah, your example gives the stack trace below. As the respect / ignore nulls
frame option is part of the window definition your example should cause two
windows to be created (both based on w, but one with the respect-nulls flag
set), but instead it fails an assert as one window definition can't have
two sets of frame options. It might take me a day or two to solve this -
let me know if this approach (making the parser create two window objects)
seems wrong.

#2 0x0000000100cdb68b in ExceptionalCondition (conditionName=Could not
find the frame base for "ExceptionalCondition".
) at /Users/xxx/postgresql/src/backend/utils/error/assert.c:54
#3 0x00000001009a3c03 in transformWindowFuncCall (pstate=0x7f88228362c8,
wfunc=0x7f8822948ec0, windef=0x7f88228353a8) at
/Users/xxx/postgresql/src/backend/parser/parse_agg.c:573

Thanks -

Nick