Live pushdown to DuckDB, query by query

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@toclocoinc/lattice-grid@1.28.0/lattice-grid.min.css">

<div id="app"></div>

<script type="module">
  import React from 'https://esm.sh/react@18';
  import { createRoot } from 'https://esm.sh/react-dom@18/client';
  import * as Lattice from 'https://cdn.jsdelivr.net/npm/@toclocoinc/lattice-grid@1.28.0/lattice-grid.esm.min.js';
  import createLatticeGrid from 'https://cdn.jsdelivr.net/npm/@toclocoinc/lattice-grid@1.28.0/modules/react.esm.min.js';

  const { createGrid, createPushdownSource, duckdbAdapter } = Lattice;
  const LatticeGrid = createLatticeGrid({ React, createGrid });

  const columns = [
    { field: 'reading_id', title: '#', type: 'number', layout: { width: 110 } },
    { field: 'plant', title: 'Plant', filter: { type: 'set' } },
    { field: 'line', title: 'Line', filter: { type: 'set' } },
    { field: 'product', title: 'Product' },
    { field: 'bore_mm', title: 'Bore', type: 'millimetres', spec: { lower: 9.95, upper: 10.05, target: 10 } },
    { field: 'cycle_seconds', title: 'Cycle', type: 'seconds' },
    { field: 'in_spec', title: 'In spec', type: 'boolean' },
    { field: 'taken_at', title: 'Taken', type: 'dateString' },
  ];

  function App() {
    const [source, setSource] = React.useState(null);
    const [status, setStatus] = React.useState('Starting DuckDB in the browser...');
    const [sql, setSql] = React.useState('');

    // DuckDB is the caller's engine, loaded from a CDN; the grid loads none of
    // it. duckdbAdapter takes the connection you made, so a hundred thousand
    // rows answer each filter and sort in SQL while the grid stays dependency-free.
    React.useEffect(() => {
      let disposed = false, connection, worker;
      (async () => {
        try {
          setStatus('Loading DuckDB from a CDN...');
          const duckdb = await import('https://cdn.jsdelivr.net/npm/@duckdb/duckdb-wasm@1.29.0/+esm');
          const bundle = await duckdb.selectBundle(duckdb.getJsDelivrBundles());
          worker = await duckdb.createWorker(bundle.mainWorker);
          const db = new duckdb.AsyncDuckDB(new duckdb.ConsoleLogger(duckdb.LogLevel.ERROR), worker);
          await db.instantiate(bundle.mainModule, bundle.pthreadWorker);
          if (disposed) return;
          connection = await db.connect();

          // The engine resolves the URL, so it must be absolute. read_parquet
          // streams the file, so a host that honours range requests lets DuckDB
          // read only the bytes a query touches.
          const file = new URL('/demo-data/readings.parquet', location.origin).href;
          const adapter = duckdbAdapter({ connection, from: `read_parquet('${file}')` });

          // Wrap execute to show the statement DuckDB ran and how long it took.
          const inner = adapter.execute.bind(adapter);
          adapter.execute = async (query, request) => {
            const started = performance.now();
            const result = await inner(query, request);
            const ms = Math.round(performance.now() - started);
            const f = adapter.sqlFor(query);
            if (!disposed) setSql(f.sql + '\n-- ' + ms + ' ms, ' + result.rows.length + ' of ' + (result.total ?? '?') + ' rows');
            return result;
          };

          setSource(createPushdownSource({
            adapter, compute: Lattice, pageSize: 200,   // only the visible window comes back, per interaction
          }));
          setStatus('100,000 rows in DuckDB. Filter a line or sort a column and the exact statement it ran shows below.');
        } catch (err) {
          setStatus('DuckDB could not start here. It loads from a CDN and needs a browser with WebAssembly and cross-origin isolation.');
        }
      })();
      return () => { disposed = true; try { connection?.close?.(); } catch (e) {} try { worker?.terminate?.(); } catch (e) {} };
    }, []);

    return (
      <>
        <div style={{ fontSize: '13px', color: 'var(--ink-2)', lineHeight: 1.5 }}>{status}</div>
        {source && (
          <LatticeGrid
            rowKey="reading_id"
            toolPanel={{ side: 'left', panels: ['filters', 'columns'] }}
            columns={columns}
            source={source}
            style={{ height: '560px', marginTop: '12px' }}
          />
        )}
        {sql && <pre style={{ marginTop: '12px' }}>{sql}</pre>}
      </>
    );
  }

  createRoot(document.getElementById('app')).render(<App />);
</script>