Le 09/02 06:55, David G. Johnston a écrit :
> On Thu, Sep 2, 2021 at 6:06 AM Charles Paperman
> wrote:
>
> I also wonder if it is problematic to have simple small query like that
> that can be design to make the database work endlessly?
>
>
>
> No, because
akes 24s a returns 20058300 rows.
This semantic for jsonpath is not so classical (other implementation choice to
return only once each selected element, in the SET semantic spirit)
and differs from the semantic of xpath, as shown here, which follows the SET
semantic:
SELECT xpath('//a//a//b', '1');
Returns:
xpath
{1}
We can of course get the appropriate semantic by adding DISTINCT, but the
initial list of rows is computed nevertheless (a O(n) algorithm exists, so it
is avoidable).
I also wonder if it is problematic to have simple small query like that that
can be design to make the database work endlessly?
Best,
Charles Paperman
Maitre de Conférence à l'université de Lille
