The bolt just needs to “put” the values into the Key-Value state that the bolt gets initialized with during “initState”. The framework automatically takes care of saving the state behind the scenes.
Theres an example in storm-starter that you might find useful - https://github.com/apache/storm/blob/master/examples/storm-starter/src/jvm/org/apache/storm/starter/StatefulTopology.java You can also find the more elaborate documentation here - https://github.com/apache/storm/blob/master/docs/State-checkpointing.md Thanks, Arun From: "Wijekoon, Manusha" <[email protected]> Reply-To: "[email protected]" <[email protected]> Date: Monday, July 24, 2017 at 4:04 PM To: "[email protected]" <[email protected]> Subject: is stateful bolts production ready? Hello I am thinking of using stateful bolts to manage state of a bolt. From the documentation it is not clear how to save the bolt state however. I understand it has to be done when we process the checkpoint tuple, but how? Do I just need to update the state object and storm pick it up during three phase commit? How does Strom know which state object to pick for check pointing? I wasn’t able to fine more complete examples either, specifically when we can’t keep the state in a kev/value map. Also, Is this functionality tested in production like environments before? Thanks M
