When working with MySQL, optimizing query performance is crucial. Before finalizing my queries, I always use MySQL Workbench to explain the query plan, ensuring optimal performance. However, I’ve noticed that performance can vary, especially with queries involving joins on multiple tables. Indexing my tables often helps, but sometimes even with appropriate indexes, the expected performance boost isn’t there. Recently, I encountered a query that wasn’t performing well despite adding the right index. MySQL Workbench revealed that MySQL wasn’t using the new index. After some experimentation, I found that using FORCE INDEX made MySQL utilize the index. However, forcing MySQL to use an index didn’t feel like the best solution. I wanted MySQL to optimize the query automatically. Discovering STRAIGHT_JOIN During my research, I came across STRAIGHT_JOIN . Adding this to my query immediately made MySQL use the index without any force. This led me to explore the differences between STRAIGHT_JOI