> It's possible to combine independent indexes for resolving AND-type
> queries, but the combination process does not preserve ordering, so
> it's useless for this type of situation.
Ok, I'm going to try the double column index. Your suggestion about the index with nulls left out worked great btw. Min/Max is instantly now.
I figure though that the double column index would not work for queries like:
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.
Regards
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