Lazy Evaluation

Since duckboat builds on top of DuckDB’s relational API, all expressions are lazily evaluated by default. This means that complex query expressions can be built up interactively and step by step, and when you are ready to evaluate the final expression (or any intermediate expressions), the query steps will be assembed and optimized by the query planner to allow for the most efficient execuation possible:

avoid materialzing intermediate tables
SQL pushdown optimizations
DuckDB streaming and out-of-core operations

Gotchas

interactive analysis that calls a repr or str method, like having a table be the last expression in a Jupyter notebook cell
IDEs that inspect variables proactively will call the repr on objects, which will trigger query evaluation. this happens in Positron, for example

Gotchas

Example