Re: RocksDB Statebackend

2016-04-13 Thread Konstantin Knauf
Hi Aljoscha, thanks for your answers. I am currently not in the office, so I can not run any further analysis until Monday. Just some quick answers to your questions. We are using the partitioned state abstraction, most of the state should correspond to buffered events in windows. Parallelism is

Re: RocksDB Statebackend

2016-04-13 Thread Aljoscha Krettek
ding, so it's > great to know that it's already on the radar. If we beat you to it, I'll > definitely try to make it a contribution. > > Shannon > > From: Aljoscha Krettek > Date: Wednesday, April 13, 2016 at 1:46 PM > To: > Subject: Re: RocksDB Statebacke

Re: RocksDB Statebackend

2016-04-13 Thread Shannon Carey
3, 2016 at 1:46 PM To: mailto:user@flink.apache.org>> Subject: Re: RocksDB Statebackend Hi Maxim, yes the plan is to have a cache of hot values that uses the managed memory abstraction of Flink so that we can make sure that we stay within memory bounds and don't run into OOM exception

Re: RocksDB Statebackend

2016-04-13 Thread Aljoscha Krettek
Hi Maxim, yes the plan is to have a cache of hot values that uses the managed memory abstraction of Flink so that we can make sure that we stay within memory bounds and don't run into OOM exceptions. On Tue, 12 Apr 2016 at 23:37 Maxim wrote: > Is it possible to add an option to store the state i

Re: RocksDB Statebackend

2016-04-12 Thread Maxim
Is it possible to add an option to store the state in the Java HashMap and write its content to RocksDB when checkpointing? For "hot" keys that are updated very frequently such optimization would help with performance. I know that you are also working on incremental checkpoints which would also be

Re: RocksDB Statebackend

2016-04-12 Thread Stephan Ewen
Concerning the size of RocksDB snapshots - I am wondering if RocksDB simply does not compact for a long time, thus having a lot of stale data in the snapshot. That would be especially the case, if you have a lot of changing values for the same set of keys. On Tue, Apr 12, 2016 at 6:41 PM, Aljosch

Re: RocksDB Statebackend

2016-04-12 Thread Aljoscha Krettek
Hi, I'm going to try and respond to each point: 1. This seems strange, could you give some background on parallelism, number of operators with state and so on? Also, I'm assuming you are using the partitioned state abstraction, i.e. getState(), correct? 2. your observations are pretty much correc