Keep Left or exists

    Keep Left or exists. which is more performant?

     

     

    I will limit my second data table based with the result of my first table. I can use either left keep or Where exists in my second table

     

     

    So,

    Solution1

    Table1:

    Load mykey from mytableA;

    Table2

    Load * from mytableB Where exists (mykey);

     

     

    Solution 2

    Table1:

    Load mykey from mytableA;

    Table2

    Keep left (Table1) Load * from mytableB;

     

     

    Result: Solution 1 is 2 times faster than solution 1

    In my example, MytableB have 9 million records

    So Exists is more performant than " left keep".