>select min(time) from transactions where payment_id is null
>So for that situation I tried whether a specific index helped, i.e. :
>create index transactions__time_payment_id__null__idx on transactions(time) where payment_id is null;
>But this does not really seem to help. It might be better to see if I can refactor the DB design though to not use nulls.
I was posting too fast again, the previous index -does- work, making the above query instant (<50ms) :) I actually mis-typed the test query before (it's rather late at my place):
select min(payment_id) from transactions where payment_id is null
Although not useful, it's an interesting case. One would say that it could return quickly, but it takes 26 minutes to execute this.
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