| From: | Andreas Tille <tillea(at)rki(dot)de> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Martijn van Oosterhout <kleptog(at)svana(dot)org>, PostgreSQL Hacker Liste <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Suboptimal evaluation of CASE expressions |
| Date: | 2006-04-11 21:22:53 |
| Message-ID: | Pine.LNX.4.62.0604112319170.3562@wr-linux02 |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Tue, 11 Apr 2006, Tom Lane wrote:
> We could maybe change things so that the finalfunc isn't run unless the
> result value is actually demanded in the SELECT list or HAVING clause,
> but for 99.99% of applications checking that would be a waste of cycles,
> so I'm disinclined to do it.
I'm lacking experience here so I perfectly trust you that keeping
the default case as it is. The question is, whether adding an
option to change the default might make sense.
> As Martijn said, really you want to fix
> the finalfunc so that it behaves sanely in corner cases. An aggregate
> that fails on zero rows needs work, period.
Fully ACK. As I hopefully made clear I just used it as a sign /
proof, that something works differently than I would regard reasonable
(before I understand the problem with the aggregate).
Kind regards
Andreas.
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