Re: Our trial to TPC-DS but optimizer made unreasonable plan - Mailing list pgsql-hackers

From Qingqing Zhou
Subject Re: Our trial to TPC-DS but optimizer made unreasonable plan
Date
Msg-id CAJjS0u2k2tNcJJwXfMGnT_+jfZK3EYdTgWOuAadNPbEgt_xT=A@mail.gmail.com
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In response to Re: Our trial to TPC-DS but optimizer made unreasonable plan  (Kouhei Kaigai <kaigai@ak.jp.nec.com>)
Responses Re: Our trial to TPC-DS but optimizer made unreasonable plan  (Qingqing Zhou <zhouqq.postgres@gmail.com>)
List pgsql-hackers
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



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