Our custom integration performs batch updates to item locations in the warehouse management module via the REST API. When processing batches larger than 50 items, we’re getting database unique constraint violations. The API returns a 500 error with a message about duplicate location assignments, but our payload validation shows no duplicates. Individual updates work fine, and smaller batches (10-20 items) succeed. We’re using BY 2023.1 and need to sync location changes from our WMS system. The error appears intermittent - sometimes batch 100 works, sometimes it fails at item 47. This is causing significant delays in our inventory synchronization process. Has anyone dealt with batch processing limits or concurrent constraint checks in the warehouse API?
Another angle: verify that your WMS system isn’t sending overlapping batches. If you have multiple integration processes running, they might be submitting concurrent batches that reference the same items or locations, causing constraint conflicts at the database level even though each individual batch is valid.
From a database perspective, the UK_ITEM_LOCATION constraint ensures each item can only be in one location at a time. If your batch includes multiple updates for the same item (even if you think they’re sequential), the database transaction isolation level might cause conflicts. The API likely wraps each batch in a transaction, and if it’s processing items in parallel threads, you’ll hit constraint violations. Check your batch for any item_id duplicates across different location assignments.
Let me provide a comprehensive solution addressing all the issues:
Batch Processing Limits: The Luminate Warehouse Management API in version 2023.1 has an undocumented soft limit of approximately 50 items per batch for location updates. Beyond this, the API’s internal transaction handling becomes less reliable. Reduce your batch size to 30-40 items maximum for consistent results. This isn’t about API throttling - it’s about database transaction management.
Unique Constraint Enforcement: The UK_ITEM_LOCATION constraint is enforced at the database level during transaction commit, not during API validation. The API validates your payload structure but can’t prevent constraint violations that occur due to concurrent operations or race conditions. To handle this:
- Pre-validate your batch for duplicate item_ids:
Set<String> itemIds = new HashSet<>();
for (ItemUpdate item : batch) {
if (!itemIds.add(item.getItemId())) {
throw new ValidationException("Duplicate item: " + item.getItemId());
}
}
- Implement idempotency checks - query current item locations before submitting batch updates to avoid conflicts with existing state.
API Error Handling: The 500 error with constraint violation indicates a database-level failure, not an API validation failure. Implement retry logic with exponential backoff:
for (int i = 0; i < 3; i++) {
try {
response = warehouseApi.batchUpdate(batch);
break;
} catch (ConstraintException e) {
if (i == 2) throw e;
Thread.sleep(1000 * (i + 1));
}
}
Payload Validation: Ensure your batch payload includes proper transaction hints:
{
"transactionMode": "sequential",
"items": [
{"itemId": "12345", "locationId": "WH-A-01-05", "operation": "move"},
{"itemId": "12346", "locationId": "WH-A-01-06", "operation": "move"}
]
}
The ‘sequential’ transaction mode forces the API to process items one at a time within the batch, preventing parallel processing race conditions.
Root Cause: Your intermittent failures (sometimes item 47 in a batch of 100) indicate a race condition. The API processes large batches using parallel threads to improve performance, but this causes constraint violations when multiple threads try to update related data simultaneously. By reducing batch size and enforcing sequential processing mode, you eliminate the parallelism that’s causing the conflicts.
Implementation Strategy:
- Split your batches into chunks of 30 items
- Add 200ms delay between batch submissions
- Include transactionMode: sequential in payload
- Implement pre-validation for duplicate item_ids
- Add retry logic for 500 errors
This approach will resolve your inventory synchronization delays while maintaining data integrity.
Interesting about the async processing. Our error looks like:
Constraint violation: UK_ITEM_LOCATION
Duplicate entry for item_id=12345, location_id=WH-A-01-05
But we’re only sending each item_id once per batch. Could the API be retrying failed items internally and causing duplicates?
We encountered similar issues. The warehouse API processes batch items asynchronously in some cases, which can lead to race conditions where multiple items try to claim the same location simultaneously. Try adding a small delay between batch submissions or reduce your batch size to 25-30 items.
The issue isn’t retries - it’s that the API validates the entire batch payload before processing but enforces constraints during individual item processing. If two items in your batch reference the same location_id (even for different operations), the constraint check can fail. Also, check if you’re sending location updates for items that already have pending location changes in the system. The API doesn’t merge operations - it treats each as independent, which can trigger constraint violations if the database state changes between validation and execution.
I’d also verify your payload structure. The warehouse API expects a specific format for batch updates with proper transaction boundaries. Are you using the ‘items’ array with individual operation objects, or are you sending a flat list? The constraint enforcement differs based on the payload structure.