topic Re: What is optimised QVD? in QlikView

What is optimised QVD?

Sat, 31 Jan 2015 01:47:47 GMT

What is optimised QVD? Thanks in advance.

Re: What is optimised QVD?

sujeetsingh — Sat, 31 Jan 2015 02:29:19 GMT

Best Practices for Data Modelling

Read this document before you go for any thing else.

So an optimised qvd is one with best loading script and performance.

It is a one with best function and dataware housing concepts.

Re: What is optimised QVD?

Colin-Albert — Sat, 31 Jan 2015 09:12:03 GMT

This link should answer your question.

QVD file Optimized..

Re: What is optimised QVD?

fkeuroglian — Sat, 31 Jan 2015 11:46:26 GMT

see this link, hope helps

Fernando

http://www.quickintelligence.co.uk/qlikview-optimised-qvd-loads/

optimize and non-optimze load in qvd

QVD file Optimized..

Turning Unoptimized Loads into Optimized Loads

Re: What is optimised QVD?

Peter_Cammaert — Sat, 31 Jan 2015 12:02:15 GMT

It's not the QVD that is optimized. IMHO QVDs do not exist in versions.

It's the manner of LOADing them that can be optimlized aka extremely fast. This usually means omitting any WHERE clauses, or using WHERE Exists() clauses with only one parameter. As long as you load columns as they are (no expressions), the LOAD stays optimized as well. Simply renaming fields is allowed too.

As soon as you use more complex column expressions or WHERE clauses, or you CONCATENATE or JOIN a QVD, the LOAD becomes un-optimized.

Peter

Re: What is optimised QVD?

Sat, 31 Jan 2015 13:51:13 GMT

Hi,

Loading the data from DB into QVD without performing any transformations is Optimized Load.

Load * from table;

Loading the data from DB into QVD with some transformations.

Load * from table where Year=2015;

Re: What is optimised QVD?

Colin-Albert — Sat, 31 Jan 2015 16:39:43 GMT

Sorry Chiranjeevi, but your answer is incorrect.

An optimized QVD load only happens when you load data FROM a qvd file into your application, and there are no data transformations or a single "where exists" clause. This can be seen in the reload progress window.

Loading from QVD files where the data is transformed, joined to other tables or other where conditions are used will not be optimised, so will load slightly slower, but faster than reloading the same data from the original source files.

You can only have a load flagged as optimized when loading from QVD files not from databases or other files.

Re: What is optimised QVD?

Anonymous — Sat, 31 Jan 2015 16:59:15 GMT

Hi,

Optimized load is much faster and therefore preferable, especially for larger data sets. Optimized QVD loads are up to 100 times quicker than non-optimized ones.

Optimized loads are possible if no transformations (calculations) are made during the load, and no (almost) filtering is done in a WHERE clause. The only acceptable filter is using function Exists: WHERE Exists (Field)

So for example this load can't be optimized: Load * From ... WHERE Country = 'US'

But this load can be optimized: Load * From ... WHERE EXISTS (Country)

For Qlikview version 10 and earlier, the only time you want the load not to be optimized, is if you load a Mapping table from a QVD file. In this case, Optimized load doesn't quite work, so you want to make the load non-optimized deliberately.

There is no concept of Optimized QVD, the qvd just has data stored in it. There is a concept of Optimized QVD load, it is the one which loads the data in QVD as such without any transformation, filtering etc.

See below links

http://www.quickintelligence.co.uk/qlikview-optimised-qvd-loads/

Optimized .QVD Confusion

http://www.citagus.com/citagus/blog/optimized-qvd-loads-in-qlikview/

Regards

Neetha

Re: What is optimised QVD?

maxgro — Sat, 31 Jan 2015 17:35:48 GMT

Optimized / non optimized refers to the load of qvd, not to the file

Optimized is (usually) faster

When you reload you can see in the script execution progress window if the load is optimized

testqvd 10.000.000 lines fetched

testqvd (qvd optimized) 10.000.000 lines fetched

this is from http://www.quickintelligence.co.uk/qlikview-optimised-qvd-loads/

(thanks to Steve Dark)

Some examples of things that will cause a non-optimised load are:

- Adding new fields to the table
– Deriving new values from a field in the QVD
– Retrieving a field twice
– Most WHERE conditions
– Joining to an existing in memory table
– Loading data into a mapping table

In contrast the things you are allowed to do are:

- Rename fields

– Omit fields
– Do a simple one field WHERE EXISTS on a field returned in the record set

Re: What is optimised QVD?

Mon, 02 Feb 2015 12:51:48 GMT

simply u can say

if u are doing all transformations while creating qvd that is qptimized qvd.

if u are doing all transformations while loading data from qvd to qvw then it is unoptimized qvd