Memory leak under Apache Benchmark load test?

[aashipov]

Please, advise on finding:
Drogon-backed app bloats up severely after multiple rounds Apache Benchmark - driven load test

To Reproduce
v1.9.12 built as per https://bitbucket.org/anatoly_a_shipov/calc/src/master/cpp-drogon/build-drogon.sh
App https://bitbucket.org/anatoly_a_shipov/calc/src/master/cpp-drogon/app.cpp
Build & run as per README.md
Launch ab test https://bitbucket.org/anatoly_a_shipov/calc/src/master/test/benchmark.sh
Watch memory consumption increase

Expected behavior
Lower memory footprint, like https://bitbucket.org/anatoly_a_shipov/calc/src/master/cpp-Crow/ (same exprtk adapter)

Desktop/Server:

• OS: Archlinux