Re: wCTE: why not finish sub-updates at the end, not the beginning?

Greg Stark <gsstark@mit.edu> writes:
> On Sat, Feb 26, 2011 at 5:55 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> So we really need some refactoring here. �I dislike adding another
>> fundamental step to the ExecutorStart/ExecutorRun/ExecutorEnd sequence,
>> but there may not be a better way. �The only way I see to fix this
>> without changing that API is to have ExecutorRun do the cleanup
>> processing just after the top plan node returns a null tuple, and that
>> seems a bit ugly as well.

> How would that handle the case of a cursor which isn't read to
> completion? Should it still execute the CTEs to completion?

Right at the moment we dodge that issue by disallowing wCTEs in cursors.
If we did allow them, then I would say that the wCTEs have to be run to
completion when the cursor is closed.
        regards, tom lane