Struct Lookup 

pub struct Lookup {
    pub over: Core,
    pub key: Core,
    pub param: VarId,
    pub index: Index,
}

One lookup, as the join that answers it.

Fields

over: Core

The collection to index, in the caller’s variables: the first argument of the map_get or of the filter_list.

key: Core

The join key, over the row the previous join in the chain produced — over the element itself for the first. This is the Fun body of crate::plan::Op::Join.

param: VarId

The parameter key is written over.

index: Index

Which index answers it, and therefore what one probe returns.