Intermittent data loss (QV not loading the full dataset from source)
For over a year now we have experienced an intermittent problem where our QV reload script returned a success result but had not loaded the full dataset from a source table.
This was eventually proven by repeatedly running the load script against a static and isolated database and comparing the number of records loaded. Occassionally (e.g. 1 in 20 reloads) the loaded data was missing some rows. Often the loss was only a few rows (tens or hundreds) but occassionally the loss was thousands. Usually on the next reload the full data was loaded. We have seen the problem on QV10 and QV11 and experienced it with Oracle, MSSQL and Access data sources but haven't tried it with others. We have recreated the problem on QV desktop and QV server. Increasing memory or changing the connection driver didn't resolve the problem.
QlikTech have acknowledged this as a high priority bug 47189 and are currently working on a fix. They have not suggested a work around or said it is something unusual in our script but our load script is VERY simple. For each table in our source database we select all the data and write it to a QVD file for consumption in other QVW documents.
TableA:
LOAD *;
SQL SELECT * FROM DataTableA;
STORE TableA INTO "DataFiles/TableA.qvd";
DROP Table TableA;
A discussion exists in the general QlikCommunity here if you want to know more
