What is the best solution for adding INDEX to speed up the query?

Question

Now I have a Query that runs 50 minutes on Mysql database and I can't accept that...

I want this process can running under 15 minutes....

insert into appianData.IC_DeletedRecords 
            (sourcetableid, 
             concatkey, 
             sourcetablecode) 
select mstid, 
        concatkey, 
        'icmstlocationheader' as sourcetablecode 
 from   appianData.IC_MST_LocationHeader
 where  concatkey not in(select concatkey 
                         from appianData.IC_PURGE_LocationHeader)

The "sourcetableid" and "mstid" are unique.

So what is the best way to add INDEX or optimize on this?

Thank you

Answer 1

I would write the select as:

select mstid, concatkey,  'icmstlocationheader' as sourcetablecode 
from  appianData.IC_MST_LocationHeader lh
where not exists (select 1 
                  from appianData.IC_PURGE_LocationHeader lhp
                  where lhp.concatkey = lh.concatkey
                 );

Then you want an index on IC_PURGE_LocationHeader(concatkey) .

Answer 2

Since it is a NOT IN condition you should be able to use a "LEFT JOIN ... WHERE rightTable has no match" without concern for multiple matches inflating the results.

INSERT INTO appianData.IC_DeletedRecords (sourcetableid, concatkey, sourcetablecode) 
SELECT m.mstid, m.concatkey, 'icmstlocationheader' as sourcetablecode 
FROM appianData.IC_MST_LocationHeader AS m
LEFT JOIN appianData.IC_PURGE_LocationHeader AS p
   ON m.concatkey = p.concatkey
WHERE p.concatkey IS NULL
;

With this version query, or the one you presented in the question, indexes on concatkey in both source tables should help significantly.