Telemetry Bench

1import { bench, describe } from "vitest";
2import { query } from "./clickhouse.js";
3import { type Reader, Cursor } from "../src/readers/core.js";
4import {
5  type TelemetryRow,
6  readTelemetryRow,
7  readTelemetryRowFast,
8} from "../src/examples/telemetry.js";
9
10/**
11 * Benchmark: API-combinator `readTelemetryRow` vs fully monomorphized
12 * `readTelemetryRowFast` over the same large buffer. The most composite-heavy
13 * example — Map + Array + Nullable + named Tuple — so the API version builds four
14 * closures per row plus a keyed object build; the biggest expected win.
15 */
16const N = 20_000;
17const BUF = await query(
18  `SELECT concat('h', toString(number)) AS host, ` +
19    `map('env', 'prod', 'az', toString(number % 3)) AS tags, ` +
20    `arrayMap(x -> toFloat64(x) / 10, range(number % 5)) AS cpu, ` +
21    `CAST(if(number % 2 = 0, 'us', NULL) AS Nullable(String)) AS region, ` +
22    `CAST(tuple(toUInt32(number), toUInt16(number % 100)) AS Tuple(start UInt32, count UInt16)) AS window ` +
23    `FROM numbers(${N}) FORMAT RowBinary`,
24);
25
26function decodeAll(read: Reader<TelemetryRow>): TelemetryRow[] {
27  const s = new Cursor(BUF);
28  const out: TelemetryRow[] = [];
29  while (s.pos < s.buf.length) out.push(read(s));
30  return out;
31}
32
33const norm = (rows: TelemetryRow[]): string =>
34  JSON.stringify(rows, (_k, v) => (v instanceof Map ? [...v] : v));
35{
36  const a = decodeAll(readTelemetryRow);
37  const b = decodeAll(readTelemetryRowFast);
38  if (a.length !== N)
39    throw new Error(`telemetry: decoded ${a.length} rows, expected ${N}`);
40  if (norm(a) !== norm(b)) throw new Error("telemetry: API vs fast mismatch");
41}
42
43describe("example telemetry: API vs optimized", () => {
44  bench("API (combinators)", () => {
45    decodeAll(readTelemetryRow);
46  });
47  bench("optimized (monomorphized)", () => {
48    decodeAll(readTelemetryRowFast);
49  });
50});