Hi, I'm experimenting a little with a TridentState implementation which persists state in a RDBMS (SQL) database, and it's working fine using paralellismHint(1).
However, increasing the TridentState paralellism leads to database deadlocks, which is unusual since I thought that, by using groupBy() before persistentAggregate(), I was making sure that every TridentState instance receives a stream of distinct values at any given point in time -- so that every instance updates those distinct keys in the database (i.e. distinct table rows), thus avoiding any database concurrency issues. Apparently, this does not work as intended. Before I continue my research any further, I'd welcome any info or hint on avoiding these deadlocks. Should I improve my TridentState implementation somewhere? I see that the State is passed the partitionIndex and numPartition parameters on initialization, which I currently don't use -- and which I suppose are the key to implementing paralellism right? Also, could you recommend an example TridentState implementation which got the paralellism right? Any help is appreciated, -- Danijel Schiavuzzi
