there are two basic ideas for implementing a StateBackend based on Redis:
 1. Rely on Redis to keep the state, use nothing else.
 2. Use Redis to keep the state and checkpoint to some distributed file
system (such as HDFS) when checkpointing

The first idea seems unwise because Redis is not a "strongly consistent
distributed data store" as Elias pointed out on the issue. The second Idea
is problematic because there is no easy way to read all state for a given
Flink operator from a running Redis instance to store it in HDFS. That's
what I was getting at in my comment.


On Fri, 7 Oct 2016 at 17:19 Ovidiu Cristian Marcu <
ovidiu.cristian.ma...@huawei.com> wrote:

> Hi
> Can you please expand the last comment:
> "I think, however, that for other reasons we will probably not be able to
> implement this well. The problem is that we have to somehow get at the
> state in redis for checkpointing. And if we use only one Redis instance for
> all states then this will be problematic." - Aljoscha Krettek
> Any other update on this issue will help, not clear the status.
> Best,
> Ovidiu

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