How to Build an Inventory Management Solution That Prevents Stock Drift

Описание и применение

Решение предотвращает расхождения запасов, обеспечивая атомарные транзакции, идемпотентность и аудитируемость изменений запасов.

Задача

Warehouse dashboards often show more available stock than the picking team can find, leading to overselling, failed fulfilment, and incorrect replenishment decisions.

Результат

The solution prevents stock drift by ensuring all inventory changes are atomic, idempotent, and auditable, reducing overselling and improving replenishment accuracy.

Рабочий процесс

• Define separate tables for inventory_balance, inventory_reservation, inventory_movement, and processed_events.
• Use a composite key on (sku, warehouse_id) to avoid duplicate balance records.
• Implement a conditional UPDATE on inventory_balance that reserves stock only if sufficient unreserved quantity exists.
• Wrap the UPDATE, reservation creation, and movement recording in a single database transaction.
• Insert a record into processed_events with a unique constraint to deduplicate events.
• If the event is a duplicate, rollback and return a duplicate flag.
• If the conditional UPDATE fails, throw an error for insufficient stock.
• Commit the transaction on success.
• Separate external notifications from database commits to avoid race conditions.
• Retry failed downstream notifications via a background worker.

Доказательства

A warehouse dashboard can show 120 units available while the picking team finds only 93.

Источник

The following PostgreSQL statement performs a conditional reservation.

Источник