Status: Resolved

Time window: approximately 04:30–10:00 Finnish time, with some store-specific variation

During the early morning AWS ElastiCache Redis maintenance window, some stores temporarily had few products missing from category and listing pages even though the products still existed correctly in the database.

The issue was caused by an edge case in recently added Redis product cache logic that coincided with an AWS ElastiCache maintenance window. In certain situations, some Redis hash entries were missing, which caused partially incomplete cached listing data.

Because no application exception occurred and the cache structure itself remained technically valid, the issue was not visible in automated tests or standard error monitoring. The main symptom was only that some products were missing from listings when they should have been visible.

Some tenants recovered automatically as caches reloaded, while others were restored after manual Redis reload or flush actions. The technical team began investigating the issue around 09:30 Finnish time. All products were fully visible around 10:00 Finnish time.

We have now improved the cache handling logic so that if a required product key is missing from Redis, the application will use the database as the backup source instead of assuming the product is missing. We also streamlined product cache invalidation and reload logic so that updates now target only the products that have changed, which improves both reliability and reload speed.

The incident is resolved. We have not been able to reproduce the original failure exactly because it appears to have started during the AWS Redis maintenance window in combination with the previous cache logic. If any product visibility issues are still noticed, please submit a support ticket with example URLs or screenshots and, if available in your environment, perform a manual Redis reload or flush.

We apologize for the disruption.