topic Performance comparison between Preceding Load and without the Preceding Load in QlikView

Performance comparison between Preceding Load and without the Preceding Load

Thu, 28 Jan 2010 02:06:31 GMT

I was able to load 4 million rows of data in 4 minutes from a database (Oracle, single table) without the preceding load box being checked but it took more than 30 minutes to load the same data with the preceding load option. In the preceding load option I have created 4 concatenated keys with multiple (2 to 3) columns. Please let me know the cause of the load time difference.

Performance comparison between Preceding Load and without the Preceding Load

rotero — Wed, 24 Aug 2011 01:26:45 GMT

anyone here can help us understand preceding load?

im newbhie and im really interested ..

Performance comparison between Preceding Load and without the Preceding Load

gandalfgray — Wed, 24 Aug 2011 09:23:09 GMT

A plain preceding load would not add any significant increase in the load execution time.

But if you start doing conversions, like creating concatenated keys it will probably increase the loading time.

An alternative way is to do any conversions (concatenating keys etc) in the SQL statement, which would be handled by the database server.

"Preceding load" is the part before the SQL statement that enumerates all the field names, and is not absolutely necessary to have.

I prefer to always use them anyway.

/gg

Performance comparison between Preceding Load and without the Preceding Load

Miguel_Angel_Baeyens — Wed, 24 Aug 2011 10:01:23 GMT

Hi,

It's been previously discussed in the Community. Check this thread to get an idea on how it works and why is highly recommendable and useful to use it.

Regards.

Miguel Angel Baeyens

BI Consultant

Comex Grupo Ibérica

N.B.: Note that that thread comes from the old forums, so some formatting may be missed.