It should be easy to transform the parse tree for

WHERE (a, b) <* (x, y)

into

a <= x AND (a < x OR b <* y)

Notes:

* <* represents either < or <=

* other operators should have similar transformations

* (a,b,c) < … — also possible, but much messier (exercise for the reader)
* This is useful only if you have an index starting with `a`. (Only `a` will be used, so including `b` is optional.)

* The index will be scanned _through_ a=x, regardless of b and y.

The optimal way to do the query is not

(a<2) OR (a=2 AND b<2)

which involves OR at the top level, hence probably a table scan. Instead, use this equivalent:

(a<=2) AND (a<2 OR b<2)

(Caveat: When there is a huge number of rows with a=2, it will still scan all the a=2 values.)

I agree. Thanks for the reference!

Thanks,
1. Haven’t tried this with 5.1
2. I do
3. Unlimited (killed query after realizing it was running for a few minutes)

Really, the restriction should be put somewhere else in the documentation, such as the index section or even where row operators are mentioned in the docs.