#501 A Nod to Sir-Mix-Alot

Topics covered in this episode:

Nod: pause your Python program and open a notebook at any line

Polars 2.0 ships: streaming engine by default, spill-to-disk, and a row-order gotcha

django-cachalot caches your ORM queries and invalidates them for you

Towards async transactions in Django

Extras

Joke

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Michael #1: Nod: pause your Python program and open a notebook at any line

Nod (Notebooks-on-Demand) is a JupyterLab extension by Eric Rawn that drops a notebook into a running Python program. Add a notebook() call anywhere, run the program with nod, and execution pauses there with a notebook containing all variables at that point in the call stack. Edits go back to the source file with a button, with cells converted to code and markdown to comments via Jupytext.

It answers the classic 'this would be easier in a notebook' debugging moment without copying snippets out to files.

Like a breakpoint with a notebook inside: the left panel walks the call stack and notebook state switches with it

Install is pip install nodpy plus nod --install-kernel, then run with nod python -m myfile

The round trip back to source is the differentiator; markdown cells become comments, cells become newlines, and notebooks are disposable since the source file recreates them

nodLog() stashes variable values across calls to explore later; the article also pitches notebook() for stepping through AI-generated code line by line

Early stage: repo from December 2025 with 16 stars and essentially one contributor, so expect rough edges

Calvin #2: Polars 2.0 ships: streaming engine by default, spill-to-disk, and a row-order gotcha

Polars 2.0 released Oct 6, 2026 (Ritchie Vink). The post says it's "not intended to be a big feature release", but it bundles a few big changes.

LazyFrame.collect now defaults to the streaming engine, with large memory and speed gains on most queries.

Breaking: streaming doesn't guarantee row order for join, group_by and unpivot. Use maintain_order=True if order matters. This is why it's a major version.

Out-of-core (spill-to-disk) is on by default. It spills at about 80% of RAM ("may need tuning") with a 64 GB default disk budget. It covers sort, window functions and many expressions. Joins and group-bys are planned, not shipped.

The new native Map dtype (Arrow MapType) replaces the old List(Struct(key, value)) reading. It comes with map.get, map.contains_key, map.len, map.keys and map.values.

Stricter by design: errors should surface up front and implicit handling of data mismatches is opt-in. collect_schema() catches schema mismatches without reading data.

SQL is now a first-class interface, with join reordering, better common-subplan elimination, and dynamic predicates/bloom filters.

Benchmarks are self-run TPC-H/TPC-DS derived numbers against DuckDB 1.5.6 and 2.0 alpha, and DataFusion 54. They are not official TPC results.

Polars was fastest on all but one benchmark. At 192 threads its constant overhead hurts small data (SF10 TPC-DS is 1.8x slower), and a fix is hoped for in the next release.

Roadmap, not released: out-of-core joins and group-bys, better scaling at high core counts, Polars Cloud, and early GeoPolars work.

Upgrade guide: https://docs.pola.rs/releases/upgrade/2/

Michael #3: django-cachalot caches your ORM queries and invalidates them for you

django-cachalot is a Django package that caches ORM queries and inval