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rapovets_A2C
Partner
Partner

Non-optimize load

Hi everybody
I can not understand because of what is non-optimize loading gvd files

the example in the attachment

Labels (4)
8 Replies
Nishanthi
Contributor II
Contributor II

Non-Optimize refers to loading of data as it is. For example,

Load

*

from table;

Optimize refers to loading of data by applying some transformations. To put it in a simple way by using a where clause you refine the load in an optimized way rather than loading all the data which will not be used. For example,

Load

*

from table where A>10;

rapovets_A2C
Partner
Partner
Author

Where exists allows optimize load

 

Nishanthi
Contributor II
Contributor II

Whatever condition you give after where clause is optimized load.......

rubenmarin

Hi, Exists() is only optimized in the one parameter version: Where Exists(FieldName)

Check if you can make it work using same field names to avoid the 2 parameters version fo Exists().

 

 

jerrysvensson
Partner
Partner

Where exist() with same field name will be optimized.
But where exists(field1, field2) will be unoptimized. As in your code.
rapovets_A2C
Partner
Partner
Author

in my code these are identical fields
goods:
load
Field1
from goods.qvd(qvd);

Sales:
load
date,
field2
from Sales.qvd(qvd)
where Exists(field1,field2);

this is optimized load
rubenmarin

In that case goods is optimized but not Sales. A workaround to make both tables optimized can be

goods:
load
field1,
field1 as field2
from goods.qvd(qvd);

Sales:
load
date,field2
from Sales.qvd(qvd)
where Exists(field2);

drop field field2 from goods;

Brett_Bleess
Support (Former)
Support (Former)

Just adding a Help link in case you still need some further explanation to get things to make complete sense here:

QVD files can be read in two modes: standard (fast) and optimized (faster). The selected mode is determined automatically by the QlikView script engine. Optimized mode can be utilized only when all loaded fields are read without any transformations (formulas acting upon the fields), though the renaming of fields is allowed. A WHERE clause causing QlikView to unpack the records will also disable the optimized load. An optimized .qvd is extracted and handled according to standard Extract-Transform-Load (ETL ) when a field transformation is performed, this results in a degradation of performance. The specified format will not be maintained and the underlying raw number format will be used instead and recognized. Transformations of the field in a .qvd is allowed, the former "Optimized" .qvd then becomes a standard non-optimized .qvd.

That is from here: http://help.qlik.com/en-US/qlikview/12.1/Subsystems/Client/Content/QVD_files.htm

Regards,
Brett

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