MySQL performance tuning for DELETE query

Cbpro Ads :

Can any one help me to re-write the query to speed up the execution time? It took 37 seconds to execute.

DELETE FROM storefront_categories 
WHERE userid IN (SELECT userid 
                FROM MASTER 
                where expirydate<'2020-2-4' 
                )

At the same time, this query took only 4.69 seconds only to execute.

DELETE FROM storefront_categories 
WHERE userid NOT IN (SELECT userid FROM MASTER)

The table storefront_categories have 97K records where as in MASTER have 40K records. We have created a index on MASTER.expirydate field.

GMB :

The query looks fine as it is.

I would suggest the following indexes for optimization:

master(expiry_date, userid)
storefront_categories(userid)

The first index is a covering index for the subquery on master: it means that the database should be able to execute the subquery by looking at the index only (whereas with just expiry_date in the index, it still needs to look at the table data to fetch the related userid).

The second index lets the database optimize the in operation.