The invoice payments report rewrite was one of the first team projects that I led as a developer at Clio.
The report is one of the most important for business operations. I had previously led a project to instrument the reporting system with monitoring, logging, and telemetry, which led us to identify this report as an under-performer. We profiled and bench-marked the existing report then built a prototype report that removed layers of abstraction to give us direct access to the data that we needed to build the report. We profiled and bench-marked the prototype to establish that building the full report would be a wise investment of resources. To establish correctness we created a complete set of inputs and outputs and built automated tests to enforce them. Once build was complete we did a final round of performance measurements and the result was a 1000% decrease in run time for the report.