The Best Practice Analyzer, part of Workbook Tools, is a useful tool for any Tableau user. It can be used like a regular check-up to auto mechanic – kicking the tires, checking the fluids and so forth. There are a lot of little things that are easy to miss that can add up to a serious lag in performance. The Best Practice Analyzer will quickly pinpoint every potential problem and flag it for you to correct.
Obviously, every new workbook that your analytics team creates should be run through the Best Practice Analyzer to see where your visualizations can be improved for better performance. With the batch selection process, we also recommend running all of the workbooks through the Best Practice Analyzer every time they are deployed.
Sometimes, you will get flags that your workbook has a potential problem, rated on a severity of Critical, Warning or Suggestion. Today, we’ll focus on how you would fix one of these Critical errors:
Non-fixed dashboard sizing causes a server performance hit
Let’s dig into what this means.
We have covered why this is a potential error in your workbook in great detail on the Power Tools for Tableau website here. In brief, Tableau Server renders every dashboard at the size they are served as a means to expedite performance. When your dashboard size is set to automatic, it will then render a new instance for each of the different sizes it produces. For a public-facing visualization, this can get quickly out of hand across desktops, tablets and smart phones.
Just to give you an idea, some common resolutions across devices include: 220×176, 320×240, 480×272, 480×320, 640×480, 720×480, 800×480, 848×480, 960×640, 1024×600, 1024×768, 1280×720, 1280×800, 1368×768, 1920×1080, 1920×1200, 2048×1538, etc.
Building a dashboard that automatically sizes to a diverse group of report consumers creates an unnecessary performance burden on Tableau Server.
Fixing the Size
The resolution for this problem comes in two parts. The first part is to set a specific size for your dashboard within Tableau Desktop. In v8.0 and later, all you have to do is select the desired dimensions from a drop-down box.
On the bottom left-hand corner of your dashboard creation screen in Tableau Desktop, there is a box titled Dashboard.
The Size drop-down offers a complete list of different pre-determined sizes that you can choose from. Alternatively, you can enter in a custom size with the w and h boxes just beneath. The default size is Automatic.
In addition, you can set a Range that will resize your dashboard between a minimum and maximum height and width. Ultimately, you can see that you might end up rendering several sizes yet again using the Range option.
We recommend that you set a fixed size, but which size is best?
Finding the Right Resolution
As is the case for all web development, you design for your audience first. The most efficient way to determine the right fixed size for your dashboards is to use a web analytics tool, such as Google Analyics, Web Trends, Omniture, etc. A standard metric in all of those reporting packages is the resolution size of the visitor (see below).
Above: Sample data from Google Analytics.
Using this sample data as the basis for our dashboards, we can see that we will properly serve nearly all of our web visitors if we set our dashboard size to 768×1024. That’s one solution, but it has a flaw.
768×1024 is the smallest resolution in our top 10. The vast majority of our users have a much larger resolution, and we’re compromising our dashboard’s effectiveness by accommodating such a small resolution. An alternative idea is to create two versions of the dashboard – one for desktop and one for tablet and smart phone. Two dashboards are still better than the myriad that you might end up with when using Automatic sizing.
The data above might lend us to create a desktop-optimized view at 1280×1024 and a mobile device-optimized view back down at 768×1024. You’ll have to decide which sizes you want to support based on the needs and uses of your report consumers.
One More Tip
Remember that the resolution of your monitor is not exactly how much space you have to create your dashboard. If you created a visualization that was exactly 1024×768 for that size of monitor, then you’re still going to end up with scroll bars because some of that screen space belongs to menu bars and other necessary items. You’ll need to reduce the size of your dashboard by approximately 20 pixels width-wise and approximately 80 pixels length-wise.
Test your visualization on the desired screen size before deployment to get your specific dimensions perfected. That way, you can avoid scrollbars and pack as much useful information as possible into your dashboard.
Finally, publish those ideal dimensions along with your data dictionary or Tableau wiki so that everyone can create a standardized dashboard size.
This is just an example of how the Best Practice Analyzer can help move your reporting team towards greater efficiency and performance. The goal of any analytics group should be to foster a culture in the hope of establishing a Tableau Center of Excellence. The Best Practice Analyzer and the entire suite of Power Tools for Tableau were designed with that in mind.
Our goal is to make the management and maintenance of your analytics capabilities as easy as possible. If you’d like more information on Best Practice Analyzer, Workbook Tools as a whole or any of our Power Tools for Tableau, contact us today.