Question

I’m trying to see if a particular hashcode is within the newest 1000 inserts for a table, what is the most efficient technique to achieve this query:

SELECT a.idsearch
  FROM searches a
 WHERE a.hashcode = 549716444      
   AND a.idsearch > (SELECT MAX(b.idsearch) - 1000 
                       FROM searches b);

idsearch is an auto_increment column and is the PK.

Answer 1

Use your existing query but add two indexes if they don’t already exist:

• A single column index on (idsearch)
• A multi-column index on (haschode, idsearch)