storage-engine-playground/tools/plan-viewer

Query Plan Viewer

A static HTML viewer for plan-runner JSON files (the fixtures). It renders the plan DAG, the input facts, and the relation computed at every plan node, so a fixture can be inspected without reading raw JSON.

Usag

Open index.html in a browser, then drop a fixture from crates/plan-runner/fixtures/ onto the page or pick one with the file input.

When the repository is served over HTTP, a fixture can also be loaded through a query parameter:

make viewer  # Or `VIEWER_PORT=9000 make viewer`
# Then open:
# http://localhost:8000/tools/plan-viewer/index.html?fixture=../../crates/plan-runner/fixtures/two_atom_join.json

What It Shows

• Plan DAG: one box per plan node, laid out left to right by join depth, with L and R labels on join inputs and the root node marked. Each box shows the node's output columns and row count.
• Selected Node: a plain-language description of the operator, its output columns, and the full relation computed at that node. Wildcard columns (names starting with an underscore) are dimmed.
• Result Bindings: the root relation projected to the fixture's expected_bindings columns, with a per-row check against the oracle and a list of any expected rows the plan did not produce.
• Input Facts: one table per relation in the fixture's schema.

The header badge reports whether the evaluated bindings match the fixture's expected_bindings as a multiset, mirroring plan_runner::verify.

Scope

The viewer re-implements the scan, semijoin, and natural join semantics of crates/query-ops and the execution order of crates/plan-runner in JavaScript, for display only. The Rust crates and their tests remain the correctness oracle; if the two ever disagree, the Rust behavior wins and the viewer has a bug.

Unsupported cases:

• plan node actions other than scan and join
• fixtures without a query and schema block