Hi, Dongwoo, I think there is no problem in this part. This part describes snapshotting Operator State, which is checkpointing. The checkpoint will store by the JobManager and use the checkpoint storage.
Best, Hang Feng Jin <jinfeng1...@gmail.com> 于2023年4月10日周一 00:32写道： > Hi Dongwoo > > > This can be quite confusing. > Before Flink 1.13, Flink's statebackend was actually a hybrid concept that > included three types of statebackends: > *MemoryStateBackend*, *FsStateBackend*, and *RocksDBStateBackend*. > > The default *MemoryStateBackend* uses heap as the backend, and the state > is stored in jobManger. > > > You can refer to this migration document for more information: > https://nightlies.apache.org/flink/flink-docs-master/docs/ops/state/state_backends/#migrating-from-legacy-backends > . > > > Best > Feng > > On Sun, Apr 9, 2023 at 10:23 PM Dongwoo Kim <dongwoo7....@gmail.com> > wrote: > >> Hi community, I’m new to flink and trying to learn about the concepts of >> flink to prepare migrating heron application to flink. >> I have a quick question about this flink document. >> ( >> https://nightlies.apache.org/flink/flink-docs-release-1.17/docs/concepts/stateful-stream-processing/#snapshotting-operator-state >> ) >> >> What I understood is states are stored in configured state backend which >> can be either task manager’s heap or rocksdb. >> And snapshots of checkpoint is stored by default in job manager’s heap >> and mostly in distributed file system. >> But in the document it says like below and it is confusing to me. Isn’t >> the second line talking about checkpoint storage or checkpoint backend? Not >> state backend? Thanks in advance, enjoy your weekend! >> >> *"Because the state of a snapshot may be large, it is stored in a >> configurable state backend >> <https://nightlies.apache.org/flink/flink-docs-release-1.17/docs/ops/state/state_backends/>. >> By default, this is the JobManager’s memory, but for production use a >> distributed reliable storage should be configured (such as HDFS)” * >> >
