After upgrading from QlikView 11 or 11.20 to 12+, load times on documents may increase. Larger documents, or at least documents with large fields containing long text strings have shown this behavior. This is due to a product enhancement in QV 12+ where text strings are checked for UTF-8 compliance on load and save, preventing uninterpreted characters by replacing them with UTF-8 compliant characters. Large fields of longer text strings will cause the app to be slower as the find/replace function of the load and save will need to traverse these fields.
Environments:
A potential fix for this was introduced into QlikView 12.20 SR 6. In this fix a global flag is introduced which must be switched on in the QlikView Server Settings.ini:
BypassTextCleanForTrusted12=1
The code will make this decision on document load: "Is this document saved in QV 12+ AND is the flag set to 1? Then, bypass search/replace function." Because the same search/replace function runs on save of the document, we can safely assume (mostly, read on) that the load will not encounter the issue and therefore skipping the check is OK. It is still better to have this turned off, so only enable this should you need to troubleshoot a document performing worse than before an upgrade.
R&D are still working on this issue, so should you have a document which performs much better after implementing this, please send it to us. More data on the issue will make for a better fix moving forward.