On Tue, Aug 18, 2015 at 5:59 PM, Kouhei Kaigai <kaigai@ak.jp.nec.com> wrote:
> BTW, did you register the patch on the upcoming commit-fest?
>
Not yet, it is in WIP status.
> I think it may be a helpful feature, if we can add alternative
> subquery-path towards cte-scan on set_cte_pathlist() and choose
> them according to the cost estimation.
>
Are you suggesting that we keep both subquery-path (whenever possible)
and cte-path so that optimizer can choose among them?
I could imagine that if we could support "materialize cte once and use
multiple times" execution, then we shall be able to benefit from
keeping cte-path. But seems we still don't support this execution
mode.
Regards,
Qingqing