What should you do if you are unsure whether an index is needed?

When facing uncertainty about the necessity of an index, the most prudent choice is to hide the index before considering deletion. Hiding the index allows you to disable it for query execution while still retaining it in the database. This approach offers a way to evaluate the performance impact of not using the index without permanently removing it.

By hiding the index, you can closely monitor query performance to see if there are any significant changes in efficiency or speed. If performance is negatively impacted, you can easily unhide the index and restore its functionality. This method provides a balance between cautious analysis and the flexibility to revert if needed, which is key in database management.

In contrast, deleting the index outright could lead to degraded performance for queries that relied on that index. Keeping the index and doing nothing may not address the uncertainty about its necessity. Recreating the index with different parameters would require more effort and not directly address the immediate question of whether the existing index is necessary. Thus, hiding the index strikes the best balance between testing and preserving the option to reinstate the index if necessary.