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MonotonicUlid vs Ulid

See original GitHub issue

Can you please tell me the use cases where a “non-monotonic” Ulid should be preferred over a “monotonic” Ulid? I expected that the generation of a MonotonicUlid is much slower than a non-monotonic Ulid, but according to the benchmark, MonotonicUlid are much faster than non-monotonic Ulids created by UlidCreator.getUlid().

Ulid_fast                              thrpt    5  34523,147 ± 1022,114  ops/ms (9.98)
Ulid_fast_toString                     thrpt    5  19161,375 ±  662,563  ops/ms
-  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
UlidCreator_getUlid                    thrpt    5   4276,614 ±   11,069  ops/ms (1.23)
UlidCreator_getUlid_toString           thrpt    5   3645,088 ±   85,478  ops/ms
-  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
UlidCreator_getMonotonicUlid           thrpt    5  32921,698 ± 1286,983  ops/ms (9.51)
UlidCreator_getMonotonicUlid_toString  thrpt    5  18541,252 ±  710,281  ops/ms

Issue Analytics

State:
Created a year ago
Comments:6 (3 by maintainers)

Top GitHub Comments

1reaction

nimo23commented, Nov 2, 2022

Oh yes the synchronized makes it slower. Good to know. Thanks!

1reaction

fabiolimacecommented, Nov 2, 2022

I implemented now the Ulid.fastMonotonic() method to test whether it is worth having a monotonic generator with SplittableRandom.

	// updates must be synchronized
	private static long lastTime = -1;
	private static Ulid lastUlid = null;

	public static synchronized Ulid fastMonotonic() {
		final long time = System.currentTimeMillis();
		if (time == lastTime) {
			lastUlid = lastUlid.increment();
		} else {
			lastUlid = fast();
		}
		lastTime = time;
		return new Ulid(lastUlid);
	}

But the throughput of Ulid.fastMonotonic() is worse (-26% less) than Ulid.fast();

------------------------------------------------------------------------
Benchmark                       Mode  Cnt      Score      Error   Units
------------------------------------------------------------------------
Throughput.Ulid_fast           thrpt    5  32754.654 ± 1276.342  ops/ms 
Throughput.Ulid_fastMonotonic  thrpt    5  24322.012 ± 1260.401  ops/ms (-26%)
------------------------------------------------------------------------

As you can see there is no performance gain, but contrary to what we expect. So I think it’s not useful because you have to synchronize the Ulid.fastMonotonic() method.

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