Check with Oracle DBAs that the user running the extraction (which may not be your user, but the one used by QlikView) has permissions to read all available lines.
Also, make sure the timeout is coming from the driver, not from QlikView itself, it could be that for some reason the server runs out of resources or there are issues with the network and then the query fails.
Thanks for quick response, Meanwhile I will check with DBA's on your suggestion.
For smaller dataset we don't face any issue, but when trying to fetch more than 100K records we encounter this problem. Another thing is we get all the records whatever has been fetched till error will be available in qvw.
Do we have any document on Qlikview & Oracle connectivity configurations