9 Replies Latest reply: Dec 22, 2016 5:46 AM by Islam Tawfik RSS

    Adding ETL to .QVD load statement decreases load times in comparison to (qvd optimized)

    Evan Kurowski

      Hello Qlik community,


      To this point the premise that optimized loads are faster than non-optimized has always held true.  From my understanding the only ETL syntax compatible with optimization is WHERE EXISTS() utilizing a single field, and aliasing of all fields except one involved in WHERE EXISTS().  Has this changed?


      I've encountered .QVDs which in side-by-side testing are reducing in the amount of time to load, when ETL statements are added to the scripting.  A sample set of about 19million loaded optimized in about 2 minutes, and normally when the optimization is deactivated, that load time might expand to around 10 minutes.  In this case, adding ETL produced reduced times (in the example Upper(), KeepChar() & a concatenation string were added, as "deactivating" syntax).


      Does anyone know what kind of circumstances could reverse load performance, and make (qvd optimized) the non-optimal result?