Performance issue: SQL Join vs. QlikView Join

[#1]

Hi All,

Currently we are joining tables in SQL query and fetching data from database.

Now we wanted to join tables in qlikview after fetching tables from database.

So the new approach will increase the perfomance load or decrease?

Please share any one you experienced the same and implementaed.

Thanks in advance,

Niranjan M.

[Gysbert_Wassenaar]

In general that will increase database performance and decrease Qlikview load performance and cause a higher network load since more data needs to be transferred to Qlikview. In cases where all your join does it add descriptions for code fields you can use applymap instead of a join. In such cases applymap can perform better than joins in either Qlikview or on the database.

[#3]

Hi Niranjan,

There isn't a 100% correct answer for that. It depends on the time it takes for the Database to perform all the joins and return the resulting dataset to QlikView (or any other tool).

If you have a powerful database and you or your colleagues have good SQL skills, it is ok to leverage this work to the database instead of QlikView.

On the other hand, if you have a decent QlikView server and you know about QV scripting, there is no problem on doing the joins in QV script. Actually, I use to do it in QV most of the times because I use to receive a database schema and the DBA's don't usually want to prepare a view because it means more work for them.

So, in your case, you will have to test both ways to do it and check how much time takes each one and how easy to implement and maintain they are.

Hope it helps.

Kind Regads,

Borja

[#4]

Hi,

It will in general increase the performance, if you use QVD for big tables and then use joins or apply map as Gysbert mentioned.

But if the intend is just to break the long query with multiple joins to different small joins, then I doubt.

You have to try both the approaches, because RAM, data, etc many factors are responsible for performance.

Thanks,

Angad