We recently discovered and fixed an issue which caused us to show slightly less data in your Funnel reports between 16/02/2018 and 30/03/2018. No data was lost and all funnel data has now been updated to show the correct values.
What effect did this issue have on my site?
The issue did not affect your website or your web visitors in any way.
What effect did this issue have on my data?
Whilst the issue was on-going, we stored but did not successfully process all log data which we use to create your Funnel reports. The effect on your Funnel visualisations would have been small, but the exact number of sessions shown at each step may have been incorrect. Based on our estimates, it's possible we showed up to 8% less data than we should have.
The number of SESSIONS (highlighted above) may have been lower.
No Funnel data was lost and our team subsequently worked to restore all previously missed log data to ensure your Funnel numbers matched the sample rate of your plan.
Why did this issue occur?
Hotjar updates Funnel reports every hour. To do this, we process all log files generated in the previous hour and update all Funnel report datasets. Unfortunately, due to the sheer amount of Funnel data being logged (we currently update over 180,000 funnel reports every hour), some of those hours weren't successfully processed over the past few weeks.
What are we doing to ensure it doesn’t happen again?
The issue was resolved by re-engineering the way we process log files to ensure we can quickly scale up as the number of Funnel reports we generate keeps increasing. We also introduced new monitoring to help us detect similar issues earlier in the future.