Once Upon A Time
I asked you to design one index to make two queries fast.
If we look at the plans with no supporting indexes, we’ll see why they need some tuning.
In both queries, the optimizer will ask for a “missing index”. That’s in quotes because, gosh darnit, I wouldn’t miss this index.
If we add it, results are mixed, like cheap scotch.
Sure, there’s some improvement, but both aren’t fast. The second query does a lot of work to sort data.
We have an inkling that if we stopped doing that, our query may get quicker.
Let’s stop and think here: What are we ordering by?
Of course, it’s the thing in the order by: Score DESC.
Where Do We Go Now?
It looks like that missing index request was wrong. Score shouldn’t have been an included column.
Columns in the include list are only ordered by columns in the key of the index.
If we wanna fix that Sort, we need to make it a key column.
Get to work.