ActiveRecord alternatives to limit due to performance issues

Question

I am experiencing performance issues when using limit on thousands of records.

Are there any alternatives too limit that active record provides or workarounds?

My query is Spot.where(<where_conditions>).limit(20)

Some solutions I have thought about;

• Using a where clause to limit the records instead where("created_at > ? and created_at < ?", 10.days.ago, 10.days.ago)

• Pluck the ids from the main where query and then make an additional query to take the top 20 ids = where(<where_conditions>).order('created_at ASC').pluck(:id) then where(id: ids.take(20)).order('created_at ASC'). The concern there would be memory usage.

Answer 1

Consider your where_condition:

• All columns in where_condition indexed? Did them indexed in right order as in where_condition?

• If you did not index all columns in where_condition. You can use deferred_join to improve performance