RDD checkpoint failures in case of insufficient memory

Hi there, A while ago running GraphX jobs I've discovered that PeriodicRDDCheckpointer fails with FileNotFoundException's in case of insufficient memory resources. I believe that any iterative job which uses PeriodicRDDCheckpointer (like ML) suffers from the same issue (but it's not visible enoug

RDD checkpoint

The checkpointed RDD computed twice, why not do the checkpoint for the RDD once it is computed? Is there any special reason for this? -- *Regards,* *Zhaojie*