geekyme / poi-pricing

A POC to test whether Apache POI is suitable for pricing

POI Pricing

A little experiment to see how we can dynamically calculate pricing with Apache POI + a spreadsheet.

Limitations

• Current implementation uses a single workbook instance preloaded into memory and protected with synchronized
• This approach heavily reduces throughput while guaranteeing safety in formula calculation
• Potential optimizations to explore:
  1. Cloned workbooks in memory to remove usage of synchronized
  2. Pool of workbooks so that concurrent threads may use a free workbook, much like socket connections
  3. Dive deeper into POI's implementation of FormulaEvaluator to see whether there are thread-safe implementations / other ways of getting cells evaluated

The spreadsheets

SimpleCalculation.xlsx - Just a simple spreadsheet with 4 values to be summed up.

AdvancedCalculation.xlsx - Advanced spreadsheet that calculates projected revenue of a clinic. With colors, macros, lots of values and formulas - A real scenario of what an actuary will produce.

Setup

1. cd api && ./gradlew bootRun

2. Simple case: GET http://localhost:8080/calculate/simple/780 or any number http://localhost:8080/calculate/simple/{value}

3. Advanced case: GET http://localhost:8080/calculate/advanced?medicard=0.1&managedCare=0.1&privateInsurance=0.2&selfPay=0.6

Run the load test

1. cd api

2. Install k6

3. Run the simple scenario with 100 concurrent users over 60s - k6 run loadtest/simple.js --vus 100 --duration 60s

4. Tested on a machine with 6 cores - Got 9-10K rps. Your results may vary. See this PR

Loadtest	Monitor

4. (Optional) to run the advanced scenario - k6 run loadtest/advanced.js --vus 100 --duration 60s. This one clocks about 700 rps

5. (Optional) to run all scenarios - k6 run loadtest/index.js --vus 100 --duration 60s