From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Improving our clauseless-join heuristics |
Date: | 2012-04-13 14:51:29 |
Message-ID: | 23665.1334328689@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> On Fri, Apr 13, 2012 at 10:32 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> After some reflection I think that the blame should be pinned on
>> have_relevant_joinclause(), which is essentially defined as "is there
>> any join clause that can be evaluated at the join of these two
>> relations?". I think it would work better to define it as "is there any
>> join clause that both these relations participate in?".
> I think it's getting a little late in the day to be whacking the
> planner around too much, but I have to admit that seems like a pretty
> good and safe change to me, so maybe we should go ahead and do it.
> I'm a bit worried, though, that with all the planner changes this
> release we are going to spend a lot of time tracking down regressions
> either in planning time or in plan quality.
Could be. I think though that this fits in pretty naturally with the
parameterized-path changes, since both of them are really directed
towards being able to apply inner indexscans in cases where we could
not before.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Stephen Frost | 2012-04-13 15:01:05 | Re: Improving our clauseless-join heuristics |
Previous Message | Robert Haas | 2012-04-13 14:46:16 | Re: Improving our clauseless-join heuristics |