Hi, thank you for your reply.
How can I ensure that the latest values are pulled from Redis the sum is updated every minute? Do I need a sliding window with an interval of 1 minute? Where would this sliding window be located in my topology? Thank you in advance. Regards, Daniela -----Ursprüngliche Nachricht----- Von: Matthias J. Sax [mailto:mj...@apache.org] Gesendet: Samstag, 9. April 2016 12:13 An: dev@storm.apache.org Betreff: Re: Use only latest values Sounds reasonable. On 04/09/2016 08:34 AM, Daniela Stoiber wrote: > Hi, > > > > I would like to cache values and to use only the latest "valid" values > to build a sum. > > In more detail, I receive values from devices periodically. I would > like to add up all the valid values each minute. But not every device > sends a new value every minute. And as long as there is no new value > the old one should be used for the sum. As soon as I receive a new > value from a device I would like to overwrite the old value and to use > the new one for the sum. Would that be possible with the combination of Storm and Redis? > > > > My idea was to use the following: > > > > - Kafka Spout > > - Storm Bolt for storing the tuples in Redis and for overwriting the > values as soon as a new one is delivered > > - Storm Bolt for reading the latest tuples from Redis > > - Storm Bolt for grouping (I would like to group the devices per > region) > > - Storm Bolt for aggregation > > - Storm Bolt for storing the results again in Redis > > > > Thank you in advance. > > > > Regards, > > Daniela > >
