AWS RDS MySQL Performance Degradation with Query Caching Enabled
I'm reviewing some code and I'm working on a project and hit a roadblock... I've been banging my head against this for hours. I tried several approaches but none seem to work. I'm experiencing important performance degradation on my AWS RDS MySQL instance (version 8.0.26) when query caching is enabled. The application heavily relies on complex joins and aggregations across multiple tables, and I've noticed an increase in latency when executing these queries after enabling the query cache. Previously, disabling caching improved response times, but I need caching to optimize specific read-heavy operations. I’ve tried adjusting the following parameters in the DB parameter group: ```sql query_cache_type = 1 query_cache_size = 1048576 ``` However, even with the cache size set to 1MB, I’m still seeing slow execution times. Running the `SHOW STATUS LIKE 'Qcache%'` command shows that the cache hit rate is around 20%, which seems low. When I look at the execution plan using `EXPLAIN`, it indicates that a full table scan is being performed, which could explain the delays. I’ve also tried adding indexes on the columns involved in the joins, but the performance scenario continues. Is there a recommended size for the query cache size for a workload like this, or could there be underlying issues affecting the performance? Additionally, are there specific practices for optimizing query performance in AWS RDS that I should consider? Any insights or examples would be greatly appreciated! For context: I'm using Sql on Linux. Any help would be greatly appreciated! My development environment is Windows. Thanks in advance! My development environment is macOS.