Some more details on this. It seems that this performance issue only occurs in QV11, in QV10 the loading time is nearly equal:
My testing measures:
CSV Load: 210 sec => 80%
QVX Load: 262 sec
CSV Load: 195 sec
QVX Load: 188 sec => 96%
I also want to mention that there are a lot of NULL values loaded from the QVX file which are empty strings if loaded from CSV. I would expect that this should be much faster..
It is very slow if field type QVX_TEXT is used! And also a problem arise when you have mixed data types in one field. Therefor I've written a Java class QVXWriter which creates QVX files identical to the files created by QlikView's STORE command (which is using field type QVX_QV_DUAL, "for internal use").
My test with 15.8M records and 21 fields (most numericals) and a size of 1.1 GB shows that this kind of QVX file loads approx. 3x faster than the CSV file although the file size of the QVX file is much bigger in this case because of the additional textual representation of numericals and dates.
I would recommend to create QVX files with this Java class in UNIX based big data environments like Hadoop, Google BIG Table etc.: