The global rate limiter was being applied at the FairQueue claim phase,
consuming 1 token per queue-claim-attempt rather than per item
processed.
With many small queues (each batch is its own queue), consumers burned
through tokens on empty or single-item queues, causing aggressive
throttling well below the intended items/sec limit.
Changes:
- Move rate limiter from FairQueue claim phase to BatchQueue worker
queue
consumer loop (before blockingPop), so each token = 1 item processed
- Replace the FairQueue rate limiter with a worker queue depth cap to
prevent unbounded growth that could cause visibility timeouts
- Add BATCH_QUEUE_WORKER_QUEUE_MAX_DEPTH env var (optional, disabled by
default)
New batch trigger system with larger payloads, streaming ingestion,
larger batch sizes, and a fair processing system.
This PR introduces a new `FairQueue` abstraction inspired by our own
`RunQueue` that enables multi-tenant fair queueing with concurrency
limits. The new `BatchQueue` is built on top of the `FairQueue`, and
handles processing Batch triggers in a fair manner with per-environment
concurrency limits defined per-org. Additionally, there is a global
concurrency limit to prevent the BatchQueue system from creating too
many runs too quickly, which can cause downstream issues.
For this new BatchQueue system we have a completely new batch trigger
creation and ingestion system. Previously this was a single endpoint
with a single JSON body that defined details about the batch as well as
all the items in the batch.
We're introducing a two-phase batch trigger ingestion system. In the
first phase, the BatchTaskRun record is created (and possibly rate
limited). The second phase is another endpoint that accepts an NDJSON
body with each line being a single item/run with payload and options.
At ingestion time all items are added to a queue, in order, and then
processed by the BatchQueue system.
## New batch trigger rate limits
This PR implements a new batch trigger specific rate limit, configured
on the `Organization.batchRateLimitConfig` column, and defaults using
these environment variables:
- `BATCH_RATE_LIMIT_REFILL_RATE` defaults to 10
- `BATCH_RATE_LIMIT_REFILL_INTERVAL` the duration interval, defaults to
`"10s"`
- `BATCH_RATE_LIMIT_MAX` defaults to 1200
This rate limiter is scoped to the environment ID and controls how many
runs can be submitted via batch triggers per interval. The SDK handles
the retrying side.
## Batch queue concurrency limits
The new column `Organization.batchQueueConcurrencyConfig` now defines an
org specific `processingConcurrency` value, with a backup of the env var
`BATCH_CONCURRENCY_LIMIT_DEFAULT` which defaults to 10. This controls
how many batch queue items are processed concurrently per environment.
There is also a global rate limit for the batch queue set via the
`BATCH_QUEUE_GLOBAL_RATE_LIMIT` which defaults to being disabled. If
set, the entire batch queue system won't process more than
`BATCH_QUEUE_GLOBAL_RATE_LIMIT` items per second. This allows
controlling the maximum number of runs created per second via batch
triggers.
## Batch trigger settings
- `STREAMING_BATCH_MAX_ITEMS` controls the maximum number of items in a
single batch
- `STREAMING_BATCH_ITEM_MAXIMUM_SIZE` controls the maximum size of each
item in a batch
- `BATCH_CONCURRENCY_DEFAULT_CONCURRENCY` controls the default
environment concurrency
- `BATCH_QUEUE_DRR_QUANTUM` how many credits each environment gets each
round for the DRR scheduler
- `BATCH_QUEUE_MAX_DEFICIT` the maximum deficit for the DRR scheduler
- `BATCH_QUEUE_CONSUMER_COUNT` how many queue consumers to run
- `BATCH_QUEUE_CONSUMER_INTERVAL_MS` how frequently they poll for items
in the queue
### Configuration Recommendations by Use Case
**High-throughput priority (fairness acceptable at 0.98+):**
```env
BATCH_QUEUE_DRR_QUANTUM=25
BATCH_QUEUE_MAX_DEFICIT=100
BATCH_QUEUE_CONSUMER_COUNT=10
BATCH_QUEUE_CONSUMER_INTERVAL_MS=50
BATCH_CONCURRENCY_DEFAULT_CONCURRENCY=25
```
**Strict fairness priority (throughput can be lower):**
```env
BATCH_QUEUE_DRR_QUANTUM=5
BATCH_QUEUE_MAX_DEFICIT=25
BATCH_QUEUE_CONSUMER_COUNT=3
BATCH_QUEUE_CONSUMER_INTERVAL_MS=100
BATCH_CONCURRENCY_DEFAULT_CONCURRENCY=5
```
Chris Arderne