Previously, the join code had to wrap the result closure into another closure to invoke Deferred::work, to deal with the fact that matches from the todo1 list had their value and diff fields swapped.
Instead of having a closure to unswap the fields, we can simply pass them to the Deferred constructor in the correct order instead. That is, the Deferred constructor should always receive the cursor/storage from input 1 first and from input 2 second. If we make this change, then a) no swapping closure is necessary, and b) the input values match the types (C1, C2) of the Deferred struct.
This PR is a backport of https://github.com/MaterializeInc/materialize/pull/19667, to avoid that the implementations diverge unnecessarily. In mz_join_core, the readability improvement from this change is more pronounced than in DD.
Previously, the join code had to wrap the
resultclosure into another closure to invokeDeferred::work, to deal with the fact that matches from thetodo1list had their value and diff fields swapped.Instead of having a closure to unswap the fields, we can simply pass them to the
Deferredconstructor in the correct order instead. That is, theDeferredconstructor should always receive the cursor/storage from input 1 first and from input 2 second. If we make this change, then a) no swapping closure is necessary, and b) the input values match the types (C1,C2) of theDeferredstruct.This PR is a backport of https://github.com/MaterializeInc/materialize/pull/19667, to avoid that the implementations diverge unnecessarily. In
mz_join_core, the readability improvement from this change is more pronounced than in DD.