ci(bench): measure the incremental benchmark as a production bundle

.github/workflows/benchmark.yml

@@ -67,8 +67,8 @@ jobs:
       - name: Run benchmark on PR
         if: steps.inputs.outputs.changed == 'true'
         run: |
-          pnpm --filter @tanstack/db-ivm build
-          pnpm exec tsx scripts/bench/incremental-update.ts \
+          pnpm --filter @tanstack/db-ivm --filter @tanstack/db build
+          node scripts/bench/production.mjs scripts/bench/incremental-update.ts \
             --iterations=100 --warmup=20 --repetitions=3 \
             --outFile="$RUNNER_TEMP/candidate.json"
       - name: Run benchmark on base
@@ -80,11 +80,12 @@ jobs:
           BASE_SHA=$(git merge-base "origin/$BASE_REF" HEAD)
           echo "Benchmarking base commit $BASE_SHA"
           git checkout --force "$BASE_SHA"
-          # Run the exact same benchmark code on both sides
-          git checkout "$HEAD_SHA" -- scripts/bench
+          # Run the exact same benchmark code on both sides, including the
+          # runner's dist freshness check
+          git checkout "$HEAD_SHA" -- scripts/bench packages/db/scripts/assert-dist-fresh.mjs
           pnpm install --frozen-lockfile
-          pnpm --filter @tanstack/db-ivm build
-          pnpm exec tsx scripts/bench/incremental-update.ts \
+          pnpm --filter @tanstack/db-ivm --filter @tanstack/db build
+          node scripts/bench/production.mjs scripts/bench/incremental-update.ts \
             --iterations=100 --warmup=20 --repetitions=3 \
             --outFile="$RUNNER_TEMP/base.json"
       - name: Compare results

scripts/bench/README.md

@@ -1,15 +1,22 @@
 # Incremental query benchmark
 
-Run `pnpm --filter @tanstack/db-ivm build`, then:
+Run `pnpm --filter @tanstack/db-ivm --filter @tanstack/db build`, then:
 
 ```sh
-node --import tsx scripts/bench/incremental-update.ts \
+node scripts/bench/production.mjs scripts/bench/incremental-update.ts \
   --iterations=100 --warmup=20 --repetitions=3 --outFile=candidate.json
 node --import tsx scripts/bench/compare-incremental-update.ts \
   --base=base.json --candidate=candidate.json --failOnRegression=true
 node --test scripts/bench/compare-incremental-update.test.mjs
 ```
 
+The benchmark measures TanStack DB as production apps run it.
+`production.mjs` bundles the benchmark against the built `dist` of db and
+db-ivm, minified, with `process.env.NODE_ENV` set to `production`, as the
+size scenarios do. Development-only code, such as full error messages and
+oracle probes, is absent, and db's private members carry their mangled names.
+The runner refuses a `dist` that is older than its package's sources.
+
 Each repetition creates fresh fixtures and queries, times their first preload,
 and measures writes after warmup. Reports retain all cold-load times and
 per-repetition write medians; displayed statistics are medians across repetitions.
@@ -53,6 +60,10 @@ for source controls, validation and limits.
 
 ## CI variation measured on 2026-11-05
 
+These runs measured db's source in development mode, before the benchmark moved
+to a production bundle. Their spread is evidence about the runners, not a
+calibration of the production-bundle timings.
+
 The [measurement table](ci-variation-2026-11-05.csv) contains query rollups from
 ten paired runs with no changes to `packages/db/src` or `packages/db-ivm/src`.
 GitHub's compare API verified that premise (each response had fewer than its

scripts/bench/production.mjs

@@ -0,0 +1,72 @@
+// Runs a benchmark as an app's production build ships TanStack DB: bundled
+// against the built packages/db and packages/db-ivm dist, minified, with
+// process.env.NODE_ENV set to `production`. Development-only code, such as
+// full error messages and oracle probes, is therefore absent, and db's
+// private members carry their mangled names. The arguments after the
+// benchmark file pass through to it:
+//
+//   node scripts/bench/production.mjs scripts/bench/incremental-update.ts \
+//     --iterations=100 --warmup=20 --repetitions=3 --outFile=candidate.json
+import { realpathSync, rmSync } from 'node:fs'
+import { mkdtemp } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import path from 'node:path'
+import { fileURLToPath, pathToFileURL } from 'node:url'
+import { build } from 'esbuild'
+import { assertPackageDistFresh } from '../../packages/db/scripts/assert-dist-fresh.mjs'
+
+const root = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '../..')
+const [benchmark, ...args] = process.argv.slice(2)
+if (!benchmark)
+  throw new Error('Usage: node scripts/bench/production.mjs <benchmark> [args]')
+
+const dbEntry = await assertPackageDistFresh(root, 'db')
+const ivmEntry = await assertPackageDistFresh(root, 'db-ivm')
+const bundleDir = await mkdtemp(
+  path.join(realpathSync(tmpdir()), 'tanstack-db-bench-'),
+)
+process.on('exit', () => rmSync(bundleDir, { recursive: true, force: true }))
+const outfile = path.join(bundleDir, 'benchmark.mjs')
+const { metafile } = await build({
+  entryPoints: [path.resolve(benchmark)],
+  outfile,
+  bundle: true,
+  minify: true,
+  sourcemap: 'inline',
+  metafile: true,
+  format: 'esm',
+  platform: 'node',
+  // Resolve imports as an app would: the repo's tsconfig paths would
+  // otherwise inline the workspace packages from their sources. The
+  // benchmark imports db's source entry for its types; the bundle takes the
+  // built entry instead.
+  tsconfigRaw: '{}',
+  alias: { '@tanstack/db-ivm': ivmEntry },
+  plugins: [
+    {
+      name: 'built-db',
+      setup(bundle) {
+        bundle.onResolve({ filter: /\/packages\/db\/src\/index\.js$/ }, () => ({
+          path: dbEntry,
+        }))
+      },
+    },
+  ],
+  define: { 'process.env.NODE_ENV': '"production"' },
+  logLevel: 'error',
+})
+
+// A source module in the bundle would measure development code, or a second
+// copy of a package beside its dist.
+const sources = Object.keys(metafile.inputs).filter((input) =>
+  /(^|\/)packages\/[^/]+\/src\//.test(input),
+)
+if (sources.length > 0)
+  throw new Error(
+    `The benchmark bundle must use built packages, but it includes sources:\n${sources.join('\n')}`,
+  )
+
+// The stack trace of a failed benchmark assertion names its source line.
+process.setSourceMapsEnabled(true)
+process.argv = [process.execPath, outfile, ...args]
+await import(pathToFileURL(outfile).href)