Alex Chi Z.

What if the course crosses two years? e.g. a 2021 fall course may span 2021 and 2022.

Overall LGTM, thanks for that!

+1, we can start with CPU / memory usage

We already have a similar one in IndexDeltaJoin PR, but it’s still under review.

Still need binder and planner support 🤪

LookupUnion is a new operator after merger. It will merge all items from each channel in order (first, second, third) instead of randomly pick one. To make life easier, I'd...

For the union all you mentioned here, it will "randomly pick one" For lookup's union, it will "merge all items from each channel in order (first, second, third)"

Also the overhead of compactor is not caused by async / await itself. It's caused by the async_trait macro, which converts all Future into Box dyn Future. If we are...

> The `poll_next` naming seems confusing to the real `Future::poll_next`. :( > > By the way, if there's no `dyn Future` on the path, I think the compiler is able...

Initially I guess the compiler somehow cannot do LTO without this PR, but I'm wrong. I removed these two lines from `Cargo.toml`. ``` codegen-units = 1 lto = 'thin' ```...