Confused about FLINK task slot

Question

I know a task manager could have several task slots.

But, what is a task slot ? A JVM process or an object in memory or a thread?

Answer 1

The answer might come late. But:

A Taskmanager (TM) is a JVM process, whereas a Taskslot (TS) is a Thread within the respective JVM process (TM). The managed memory of a TM is equally split up between the TS within a TM. No CPU isolation happens between the slots, just the managed memory is divided. Moreover, TS in the same TM share TCP connections (via multiplexing) and heartbeat messages. They may also share data sets and data structures, thus reducing the per-task overhead.

Source: https://ci.apache.org/projects/flink/flink-docs-release-1.5/concepts/runtime.html#task-slots-and-resources