Incremental load is very important load among all loads in qlik. Whenever if we reload the application in qlik it will hit the db and get the complete information from the beginning to the till date.
Let assume I will hit the DB today and the entire information I am going to save in the QVD. I am not refreshing or reloading the same application may be for 10 days.
Now after 10 days if i again reload the application it will again hit the DB and gets the information from the beginning to the till date which you reloaded. It means we are unnecessarily getting the previously loaded information again and again to the recently loaded application.
So instead of getting old data again and again from the DB to the application by using with Incremental load concept we will restrict old data not to load in our application is nothing but incremental load.
To achieve this we have 3 components in incremental load
Incremental insert
Incremental update
Incremental delete