Re: Flink message & state lifecycle.

2016-01-16 Thread Andrew Coates
Fantastic. Sounds like things are moving in the right direction. I'm hoping this will be tiered storage. Thanks! On Fri, 15 Jan 2016, 17:04 Aljoscha Krettek wrote: > Hi, > don’t worry, it’s good to get questions about this stuff. :D > > You are right, if Flink is not clever about the state your

Re: Flink message & state lifecycle.

2016-01-15 Thread Aljoscha Krettek
Hi, don’t worry, it’s good to get questions about this stuff. :D You are right, if Flink is not clever about the state your JVMs can run out of memory and blow up. We are currently working on several things that should make this more robust: 1) Put Flink Windows on Flink’s partitioned state abst

Re: Flink message & state lifecycle.

2016-01-15 Thread Andrew Coates
Hi Aljoscha, Just thinking on the EventTimeTrigger example you provided, and I'm going to apologise in advance for taking more of your time!, but I'm thinking that should I go down that route any long allowedLateness, we'll run into issues with memory use, unless Flink is smart enough, configurab

Re: Flink message & state lifecycle.

2016-01-15 Thread Andrew Coates
Hi Aljoscha, Thanks for the info! Andy On Fri, 15 Jan 2016 at 10:12 Aljoscha Krettek wrote: > Hi, > I imagine you are taking about CountTrigger, DeltaTrigger, and > Continuous*Trigger. For these we never purge. They are a leftover artifact > from an earlier approach to implementing windowing s

Re: Flink message & state lifecycle.

2016-01-15 Thread Aljoscha Krettek
Hi, I imagine you are taking about CountTrigger, DeltaTrigger, and Continuous*Trigger. For these we never purge. They are a leftover artifact from an earlier approach to implementing windowing strategies that was inspired by IBM InfoSphere streams. Here, all triggers are essentially accumulating

Re: Flink message & state lifecycle.

2016-01-15 Thread Andrew Coates
Thanks Aljoscha, that's very enlightening. Can you please also explain what the default behaviour is? I.e. if I use one if the accumulating inbuilt triggers, when does the state get purged? (With your info I can now probably work things out, but you may give more insight :) Also, are there plans

Re: Flink message & state lifecycle.

2016-01-13 Thread Aljoscha Krettek
Hi, the window contents are stored in state managed by the window operator at all times until they are purged by a Trigger returning PURGE from one of its on*() methods. Out of the box, Flink does not have something akin to the lateness and cleanup of Google Dataflow. You can, however implement

Flink message & state lifecycle.

2016-01-13 Thread Andrew Coates
Hi, I'm trying to understand how the lifecycle of messages / state is managed by Flink, but I'm failing to find any documentation. Specially, if I'm using a windowed stream and a type of trigger that retain the elements of the window to allow for processing of late data e.g. ContinousEventTimeTri