Module lookup 

MongoDB on-demand lookup source for cache-miss fallback.

Implements LookupSource via a multi-get on the indexed key (find({ pk: { $in: [keys] } })), so all missed keys of a probe fold into one round trip. MongoDB is schemaless, so the source projects each returned document into the table’s declared Arrow schema (from CREATE LOOKUP TABLE); KeyAligner handles key decode and realignment.

v1 limits: single-column key; declared column types Int32/Int64/Float64/ Boolean/Utf8 (others render as a string/JSON fallback or NULL).

Structs

MongoLookupSource

MongoDB lookup source for on-demand/partial cache mode.

MongoLookupSourceConfig

Configuration for MongoLookupSource.