Backend Integration

The MonadArbiter typeclass separates the core from database libraries. Arbiter provides three adapters: arbiter-simple, arbiter-orville, and arbiter-hasql. Use the adapter for the database library in your application if you want to share connections.

Benchmarks

Jobs/sec with arbiter-hasql, prepared claims, PostgreSQL 18, GHC 9.14.1, Apple M5 Pro. Single-job mode / batched mode (batch size 10).

Pre-loaded queue (1M jobs, 4 pools × 10 workers):

Queue	Single	Batched
ungrouped	10,491	39,918
ungrouped, dormant	10,407	40,219
50k groups	8,116	31,559
50k groups, scheduled + backoff	2,550	22,126
50k groups, dormant	8,106	30,878

scheduled + backoff: a fifth of jobs scheduled seconds out, a fifth failing once into backoff. dormant: half the backlog parked 30 days out.

Steady state (10 producers inserting continuously, 4 pools × 10 workers):

Queue	Single	Batched
ungrouped	10,143	16,940
ungrouped, OpenTelemetry on	9,522
5k groups	5,322	16,547
5k groups, scheduled + backoff	2,302	12,685

Group size and skew (300k jobs, 4 pools × 10 workers):

Groups	Single	Batched	Group triggers, µs/job
1 job/group	8,475	6,840	328 / 429
10 jobs/group	8,364	35,637	353 / 66
100 jobs/group	6,807	36,867	352 / 72
1,000 jobs/group	3,209	24,857	417 / 48
10,000 jobs/group	888	9,791	511 / 60
80/20 skew, 1k groups, 10 hot	2,719	17,043	577 / 87

Admission gating (steady state, 10 producers, 256 keys):

	no gate	rate limit	concurrency	both
ungrouped, single, 1 pool	4,027	2,946	2,162	1,831
ungrouped, single, 4 pools	5,318	5,346	3,686	2,736
ungrouped, batched, 1 pool	16,521	10,304	7,659	6,246
5k groups, single, 1 pool	831	871	688	661
5k groups, single, 4 pools	2,270	2,220	1,987	2,011
5k groups, batched, 1 pool	5,512	5,188	3,735	3,379

One pool is 10 workers and one dispatcher.

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Arbiter

Backend Integration

Benchmarks