Deleting duplicate subscribers using max uuid postgresql
Here is a generic method that works as long as there is a lower-than operator on the column used to discriminate  (which is the case of uuid). 

WITH dups as (
  select email, id FROM...&lt; complete this with the duplicates detection&gt;
)
DELETE FROM subscribers USING dups
WHERE dups.email = subcribers.email
  AND dups.id &lt; subscribers.id;


You may replace id by a creation timestamp if these timestamps are guaranteed to be different. Even if they're not different, meaning there are (email,timestamp) duplicates, they will just be not touched by this DELETE. You can then do a second pass with another DELETE, this time with the uuid as the differentiator as in the query above. If the timestamps were all different this 2nd pass will delete nothing, otherwise it will finish the job.

Also you may do this in a transaction and check if there are still duplicates and the number of deleted rows seem good before doing a COMMIT or ROLLBACK.