QlikView App Dev

[#1]

Hi Experts,

I am new to QlikView have difficulty to understand for QVD.

1. What is the QVD Optimized?
2. What is the Non-Optimized?
3. When an optimized load into QV?
4. When a Non-optimized load into QV?
5. Why not make all loads from QVD optimized?
6. Why not make all loads from QVD Non-optimized?
7. How (critical it is) to ensure our loads from QVD are optimized or optimized or not?
8. When QVD optimized - QVD file has created any INDEX (what happened inside into QVD file).
9. When the incredible speed of an optimized load is really essential
10. Loading data into QlikView application QVD file will be 10-100 then pulling data direct from other source HOW?
11. What is Fast QVD?
12. What is the SUPER fast QVD?
13. Incremental load only possible using QVD(suppose source only DB ,not into QVD like 2  Tier) any other way?
14. Able to  join the two or more QVD into one QVD file?

Regards,

Raja.

[hic]

The QVD file format is just a binary, compact format to store one single table in a file. When you load it - and you don't make any changes - it loads optimized, i.e. extremely fast. But if you make any transformations, or unpacks record-wise data in the Load statement, it loads slower; it loads non-optimized. That's all.

Apart from this, you can use a QVD file in the same way as a CSV: concatenate them, join them, etc.

HIC

[jagan]

Hi,

When you are loading data from QVD without any changes then it is called Optimized load, i.e., it loads very faster, if you doing any transformation, calculations, filtering using where condition, sorting then it is called Non Optimized load.

Hope it helps you.

Regards,

Jagan.

[#4]

Hi Raja.

1. What is the QVD Optimized? - That basically means that Qlikview created the QVD sorted and compressed etc. in such a way that it is easy and faster to use in Qlikview.
2. What is the Non-Optimized? - a QVD is created that is not optimized as mentioned above for Qlikview.
3. When an optimized load into QV? - When using a layered approach to your development. It is usually when you have a "loader" QVW ( Qlikview Model) that loads the data from the source and then creates Qlikview Optimized QVD files to be used in models. I prefer to use Qlikview optimized QVD's over non optimized.
4. When a Non-optimized load into QV? - See above
5. Why not make all loads from QVD optimized? - when loading a lot of data form a data source there is a definate advantage to creating Qlikview optimized QVD's and then using them. However in some instances when you use a small excel file for something it is not needed. There will then be no significant gain in performance.
6. Why not make all loads from QVD Non-optimized? - See Above
7. How (critical it is) to ensure our loads from QVD are optimized or optimized or not? - Depending on the size and the load times as well as the development and deployment environment used. When there are more than one Qlikview model that uses the same fields it is better to create the QVD's. This will reduce the strain on the data source servers as well as ensure that the models balance with each other. ( Sales figures in a sales model will then balance to the Sales figures of a Revenue model.) This can be the difference between having all your models loaded and ready to use before the start of the business day and the models still loading half way through the day.
8. When QVD optimized - QVD file has created any INDEX (what happened inside into QVD file).
9. When the incredible speed of an optimized load is really essential - When working with very large tables. loading 300million rows of data from the data source takes a lot longer than from a qvd.
10. Loading data into QlikView application QVD file will be 10-100 then pulling data direct from other source HOW? - Not sure what you mean here ?
11. What is Fast QVD? - the fast and super fast QVD ( as far as I know ) has to do with the compression levels used when creating the qvd file. The faster the qvd the less compression is used.
12. What is the SUPER fast QVD? - See above
13. Incremental load only possible using QVD(suppose source only DB ,not into QVD like 2  Tier) any other way? - Not sure
14. Able to  join the two or more QVD into one QVD file? - It depends on the tables that you want to join and create a single table. If you have sales from a couple of regions, and the tables for all of the regions come from diffident database sources. Then if they have the same fields in all of them you can concatenate all of them into one to view a National sales value. It is also possible to create a single table by joining "related" tables. This will create a table with more columns and a larger table. It is definately doable however you need to carefully look at the impact that will have on the resources available. Lets say you want to add a the ITEMS table into the SALES table. The sales table currently only has the ITEM_NO in it. In the ITEMS table there are more fields eg. ITEM_NO, ITEM_DESCRIPTION,ITEM_UOM,ITEM_PRICE.  Now lets say the SALES table has 10mil lines in it and there are only 5 ITEMS in the ITEMS table. When you join in stead of only having that 5 values x 4 columns it will be 4 columns x 10 mil. ( PS. it would not make sense to add the Items table to the Sales table, this was just for illustration)

[hic]

"Optimized" has nothing to do with how the QVD is created. There is no such thing as an "optimized file" or a "non-optimized file". The only thing that matters, is how the QVD file is loaded - whether the Load statement contains expressions that forces QlikView to unpack the QVD during the Load sequence.

HIC