Leaking H2 internals when querying from pyignite

I am sharing a slightly modified reproducer from userlist.

To run:

Start a node (with JVM_OPTS=-Xmx512m to see it most clearly).
Run a .sql file with sqlline (!run)
python3 test_insert_in_cache.py
in parallel terminal: python3 read_cache_insert_update_table.py

Then you should observe slowing down and long GC pauses on server node. jmap will collect ever-increasing heap dumps.