| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Richard Guo <guofenglinux(at)gmail(dot)com> |
| Cc: | David Rowley <dgrowleyml(at)gmail(dot)com>, Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com>, Ronan Dunklau <ronan(dot)dunklau(at)aiven(dot)io>, Justin Pryzby <pryzby(at)telsasoft(dot)com>, Pavel Luzanov <p(dot)luzanov(at)postgrespro(dot)ru>, pgsql-hackers(at)lists(dot)postgresql(dot)org, Ranier Vilela <ranier(dot)vf(at)gmail(dot)com> |
| Subject: | Re: Add proper planner support for ORDER BY / DISTINCT aggregates |
| Date: | 2023-01-17 07:05:19 |
| Message-ID: | 2909364.1673939119@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Richard Guo <guofenglinux(at)gmail(dot)com> writes:
> BTW, I wonder if we should have checked CoercionForm before
> fix_upper_expr_mutator steps into CoerceViaIO->arg to adjust the expr
> there.
I will just quote what it says in primnodes.h:
* NB: equal() ignores CoercionForm fields, therefore this *must* not carry
* any semantically significant information.
If you think the planner should act differently for different values of
CoercionForm, you are mistaken. Maybe this is evidence of some
previous bit of brain-fade, but if so we need to fix that.
regards, tom lane
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