Meltdown & Spectre impact on Qlik products

By Barry Harmsen

Meltdown and Spectre are two vulnerabilities disclosed in early 2018 that affect nearly every processor manufactured in the last 20 years. The initial assessment was that patching these vulnerabilities could in some cases lead to a 30% performance decrease on server workloads. Those are very serious numbers!

This may read like old news, but new patches have become available and some recommendations have changed. It is a good idea to regularly check up on these issues and avoid further problems.

How do Meltdown and Spectre impact QlikView / Qlik Sense?

First of all, this is not a QlikView or Qlik Sense vulnerability, but it can impact their performance. Our own initial tests suggested that the impact was fairly minimal, but the folks at Qlik Support and the Qlik Scalability Center are reporting numbers between 4 and 20%. With the higher performance impact being experienced on larger, more heavily-loaded servers (the kind that we don’t have lying around in our lab ;).

Qlik Support has a very good write-up of their findings here, which they have updated as new information has become available. I highly recommend to regularly check for updates on this page


Have you noticed impact on performance?

Of course, I am very interested in hearing your experiences with these issues as well. Have you noticed any significant performance decreases? If so, can you share some information about the environment, hardware and specific circumstances (if any) where this occurs? Feel free to leave a reply below!


On a side-note, for those of you interested in how these vulnerabilities work, the Raspberry Pi Foundation has a very good write-up here.