Add to cart much slower in Commerce 3 vs. Commerce 2 (and other requests)

[bossanova808]

Description

Adding items to cart...was near enough to instant with Commerce 2.

With Commerce 3, takes a minimum of a few seconds every time, same server and templates etc. It's just a lot slower.

Indeed, am noticing a distinct slow down in all cart related operations - increasing qtys, removing items, etc. Definitely a noticeable performance drop across the board on the front end.

In the profiler for these ajax operations, I am seeing a great number of queries that are slower than I'd expect (16ms+), and many of them repeated...including, e.g., ones summing refunds (which seems unnecessary for a not-yet-completed order!)

Any tips of trying to work out where the issues are coming from and what I can do to re-gain performance would be great. It's slow enough and different enough I am quite sure we're going to be getting issues from customers about it.

[lukeholder]

Should be fixed in #1543

[bossanova808]

Do you folks know when you might cut a release? Debating going to the develop version in the meantime....

[lukeholder]

@bossanova808 will be tonight/in the morning.