MySQL indexes - how many are enough?

Question

I\'m trying to fine-tune my MySQL server so I check my settings, analyzing slow-query log, and simplify my queries if possible.

Sometimes it is enough if I am indexi

Answer 1

There's no magic number for the "best" number of indexes. The basic rule is this: add indexes for queries that are used often and/or need to run quickly.

Having "too many" indexes shouldn't slow down queries, but it each index added adds a small amount of time to add/update items in the db (since it modifies the indices as well), and a small amount of space. However, if you're just adding indexes as required, this is probably not a big concern.