Constant PYTHON_DDL 

pub const PYTHON_DDL: &str = "
CREATE TABLE IF NOT EXISTS gil_events (
    id              INTEGER PRIMARY KEY,
    session_id      TEXT NOT NULL REFERENCES sessions(id),
    kind            TEXT NOT NULL,
    thread          TEXT,
    start_us        REAL,
    duration_us     REAL,
    layer_id        INTEGER REFERENCES layers(id)
);
";

Python-specific tables (GIL contention).