The JobManager and TaskManager

JobManager works like a work scheduler. It collects work and then assigns it to a task manager, which breaks each work down into multiple tasks, which can be broken down into subtasks. In Flink, a task manager is a JVM process, and each JVM process contains multiple Taskslots. A TaskSlot represents a resource set of a fixed size for a JVM process, and these Taskslots can perform various subtasks.

By default, Flink allows subtasks to share slots. Although they come from different tasks, they must come from the same Job. A Job scheduler runs a Flink Job

The Savepoint and Checkpoint

Programs written using the Data Stream API can recover from a Savepoint, which is similar to a checkpoint and is used to save status, according to Flink: The difference between savepoints and checkpoints is that savepoints are manually triggered by the user and do not expire automatically when a new checkpoint is created, whereas checkpoints are timed by the work scheduler

Development considerations

Question list

  1. java.lang.NoClassDefFoundError: org/apache/flink/table/api/TableEnvironment

Solution: Edit Con