The join optimizer may produce an IndexProbeNode when constructing an INLJ plan. Currently this node has an IndexEntry to represent which index the probe will use. However, we are forced to construct this object as the join optimizer only has the IndexCatalog from the MultiCollectionAccessor. The SBE stage builders don't need this entire structure, they only need the index ident to construct the plan. We should consider storing a simpler structure in the IndexProbeNode to represent the index to avoid unnecessary work. Just storing the ident is not enough information for explain.