Incremental load

[#1]

I read that i can use the exist () phrase for a qvd load and still the qlikview will load the qvd as "optimized Load".

So if i'll replace the "where DateField > $(VDate)" part in an incremental load statment with "where exist (AlreadyLoadDateField)" i will get better performance ?

did someone use it or try it out ?

thanks for your help.

[#2]

Can someone help me with this ?

[gandalfgray]

Yes I think you would.

But You should rather use Not.

...

Where Not Exists(DateField);

/gg

[#4]

i dont think you will get better performance! because if you load from a source (except a qvd-file) with the "not exists"-statement, the script has to load all the data from the source and then filter the already existing datasets out of it. if you load with an "where DateField > $(VDate)"  statement, then the source maybe can filter the datasets for itself and only submit the correct Data to your script. Therfore not so much data has to be streamed.

MFG

[gandalfgray]

... well I thought "a qvd load" meant that Matan was loading from a qvd...

If it's a load from a relational database, the performance will depend on the indexes in the database etc.

/g

[#6]

Thanks for your comments.

I probably didnt make my self clear.

I know that the part in the script that load the new data from relational database will not be affected by using exist () insted of "where DateField > $(VDate)" .

in the second part - the loading of the saved data (stored in qvd) i want to load the old data without the last saved day.

for that part i considered of using the exist () phrase.

so...will it work better ?

[gandalfgray]

If you have first loaded data (by sql or something) into a field DateField

you could then load from a qvd using

Where Not Exists(DateField)

to avoid loading records with DateField-values that is already loaded into your qvw.

I believe it should be faster than

Where DateField>$(VDate)

hth/gg

[#8]

Thank a lot