Looking at your queue management metrics showing 500+ pending messages, you definitely need a multi-pronged optimization approach. Let me walk through the complete solution addressing all the bottlenecks.
For ION message processing, increase your worker threads and connection pool. Based on 2000 transactions/hour, you need at least 40-50 database connections. Update your ION configuration:
MaxConcurrentMessages=100
ConnectionPoolSize=50
MessageProcessingTimeout=30000
For database write optimization, implement batch processing instead of individual inserts. This reduces round-trips and improves throughput significantly. Your application should queue inventory updates and commit in batches every 2-3 seconds rather than immediately.
For API Gateway caching, you need selective caching - not all-or-nothing. Configure cache headers for inventory endpoints:
Cache-Control: max-age=5, must-revalidate
X-Cache-Strategy: write-through
This allows 5-second caching for reads while ensuring writes invalidate immediately. For your specific warehouse scenario, enable write-through caching so updates propagate to cache synchronously.
For queue management, implement priority routing. Inventory transactions should use a dedicated high-priority queue separate from other business documents. In ION, create a separate connection point specifically for warehouse operations with higher resource allocation.
Additional optimizations: Enable ION message compression to reduce network overhead, implement database connection pooling with connection validation, and consider partitioning your inventory tables by warehouse location if you have multiple sites.
Monitor your improvements using ION Analytics. You should see queue depths drop below 50 messages and processing latency under 30 seconds within peak hours. If you still see delays after these changes, the bottleneck may be at the database level - check for missing indexes on InventoryTransaction and StockLevel tables.