What should be done if the join type is 'all'?

When the join type is set to 'all', this typically means that the query will return all records from the specified tables, potentially leading to large result sets, especially when multiple joins are involved. In such scenarios, performance can be significantly impacted due to the high volume of data being processed and returned.

Adding relevant indexes is crucial in this case since indexes can greatly enhance the performance of queries involving joins. By applying indexes to the columns involved in the join conditions, the database can more efficiently locate the rows needed to produce the result set. This can reduce the amount of time and resources required to execute the query and return results, ultimately improving the overall responsiveness of the application.

Indexing is a foundational practice in optimizing database queries, especially when dealing with extensive datasets and comprehensive queries like those using 'all' joins. This step is essential to ensure that the application behaves efficiently and delivers a good user experience.