topic Re: load data using exist taking too long in QlikView

load data using exist taking too long

Sun, 06 Jan 2013 14:00:43 GMT

i am working with Sql server DB.

I have two table :

1. I load table from QVD - work very fast

Failures:

Load * from $(path_xls)Failures.qvd(qvd);

2.load table from sql server using "where exist "

so that i will get only the serial_number which exist in the earlier table i load (QVD)

and it is taking too long , why ?

Is there a way to speed it up ?

FACT_CUSTOMER:

LOAD

"Serial Number" as Serial_Number,

"Part Number",

"Imp (Y/N)",

"Color Imp (Smoothed)"

WHERE exists(Serial_Number,"Serial Number");

SQL SELECT *

FROM xxxx.dbo."DW_FACT_CUSTOMER";

Thank you

Re: load data using exist taking too long

jonathandienst — Sun, 06 Jan 2013 14:41:23 GMT

The first load is an optimised load from a QVD file. This is the fastest possible load from an external data source into QV (assuming that the QVD file is local to the machine performing the load and not network limited).

The second load is from a SQL source, and the speed here is determined by the SQL server, the ODBC or OLEDB driver and the network connection, whichever is slowest. It is possible that the Exists is also playing a part, but I expect that tp be a minor factor. To test the exists, don't compare to the QVD load, but run the second LOAD without the exists.

Bear in mind that SELECT * will return all fields from the database, and (as there is no where clause) every row in the table. The Exists is only performed after all the data has been loaded from the database table into QV.

Hope that helps

Jonathan

Re: load data using exist taking too long

Mon, 07 Jan 2013 06:07:02 GMT

thank you