pub fn query_memory_limit_from_env() -> Option<usize>Expand description
Resolve the default per-engine memory limit from the
KRISHIV_QUERY_MEMORY_LIMIT_BYTES environment variable, falling back to
a cgroup-derived default when the variable is unset.
Fallback: 25% of the container’s cgroup memory limit (v2 memory.max,
v1 memory.limit_in_bytes). Several engines can be live in one process
(executor task slots, the Flight SQL host, IVM ticks), so a single
engine’s pool must not claim the whole container. Explicit 0 disables
the limit entirely (DataFusion’s default unbounded pool); an unlimited
cgroup (no limit / max) also yields None.