Memory Leak

The following discussion from !465 (merged) should be addressed:

• @palmb started a discussion: (+8 comments)

  Anyways the increase in memory usage seems to be acceptable: With data of size (10, 5_000_000) and a single test on every column increases the memory usage from ~1_730_000 to ~ 2_094_000 in steps of ~20_000 bytes per function call.

  can you provide how you test test the memory..