We don't run a TSDB. A TSDB doesn't work for the kinds of queries we run - specifically, TSDBs don't work if you want to

  * analyze every datapoint you receive
  * when the dimensional cardinality is high
  * you want to analyze behaviors over time (e.g. the output depends on the orders of events followed - like creating a funnel report)

There's no off-the-shelf solution that does this at the scale at which we operate - hence the need to write our own custom solution.