When using the Copy to URL function on a chart, it provides a short link to the chart. However, in some cases, that short link expands to a really long link that overflows the length of a request.
For example, https://analytics.frdev.wikimedia.org/r/2390 ends up with a url that tosses the following error
Bad Request Request Line is too large (4326 > 4094)
We may wish to look at adjusting this to handle some of our really large charts. Also, it's possible we won't want to.