Edmund Horner writes:
> On Sat, 22 Dec 2018 at 12:34, Tom Lane wrote:
>> I decided to spend an afternoon seeing exactly how much work would be
>> needed to support parameterized TID scans, ie nestloop-with-inner-TID-
>> scan joins, as has been speculated about before, most recently here:
>> ...
On Sat, 22 Dec 2018 at 12:34, Tom Lane wrote:
> I decided to spend an afternoon seeing exactly how much work would be
> needed to support parameterized TID scans, ie nestloop-with-inner-TID-
> scan joins, as has been speculated about before, most recently here:
>
> https://www.postgresql.org/messa
Hi,
Writing as someone who used TID joins and group by's in the past.
One use case is having a chance to peek into what will DELETE do.
A lot of GIS tables don't have any notion of ID, and dirty datasets tend to
have many duplicates you need to cross-reference with something else. So,
you write y
On Sat, 22 Dec 2018 at 16:31, Tom Lane wrote:
> What I'm thinking about in this thread is joins on TID, which we have only
> very weak support for today --- you'll basically always wind up with a
> mergejoin, which requires full-table scan and sort of its inputs. Still,
> that's better than a n
Simon Riggs writes:
> On Sat, 22 Dec 2018 at 04:31, Tom Lane wrote:
>> BTW, if we're to start taking joins on TID seriously, we should also
>> add the missing hash opclass for TID, so that you can do hash joins
>> when dealing with a lot of rows.
> I don't think we are trying to do TID joins mor
On Sat, 22 Dec 2018 at 04:31, Tom Lane wrote:
> BTW, if we're to start taking joins on TID seriously, we should also
> add the missing hash opclass for TID, so that you can do hash joins
> when dealing with a lot of rows.
>
> (In principle this also enables things like hash aggregation, though
>
BTW, if we're to start taking joins on TID seriously, we should also
add the missing hash opclass for TID, so that you can do hash joins
when dealing with a lot of rows.
(In principle this also enables things like hash aggregation, though
I'm not very clear on a use-case for grouping by TID.)
