On Wed, May 17, 2017 at 8:38 PM, Heikki Linnakangas wrote:
>
> As a final note, I found an interesting paper called "Unnesting Arbitrary
> Queries", by Thomas Neumann and Alfons Kemper
> (http://www.btw-2015.de/res/proceedings/Hauptband/Wiss/Neumann-Unnesting_Arbitrary_Querie.pdf).
> It describes
On 18 May 2017 at 04:30, Robert Haas wrote:
> On Wed, May 17, 2017 at 11:08 AM, Heikki Linnakangas wrote:
>> That's not a straight semi-join, but we could still turn it into a new kind
>> of LEFT-SEMI join. A left-semi join is like a left join, in that it returns
>> all rows from the left side, a
On Wed, May 17, 2017 at 11:08 AM, Heikki Linnakangas wrote:
> That's not a straight semi-join, but we could still turn it into a new kind
> of LEFT-SEMI join. A left-semi join is like a left join, in that it returns
> all rows from the left side, and NULLs for any non-matches. And like a
> semi-jo
Hi,
I spent some time staring at TPC-DS benchmark's query 6. It contains a
somewhat complicated subquery, and most of the time spent on that query
is currently spent on executing the subquery again and again. The
essence of the query boils down to this:
CREATE TABLE foo (i int4, j int4);
CRE
