Re: Timer coalescing necessary?

Hi, Because of how they are triggered by the watermark, all event-time triggers with the same timestamp will be triggered in the same go, without interleaving other calls. Same is true for processing-time triggers because they "piggy back" on the one "physical" processing-time service trigger.

Re: Timer coalescing necessary?

Hi, Thanks for the explanation. Because timer callback and normal execution are not guarantee to be concurrent-safe, if we have multiple timers with the same timestamp, are all of them run before the normal execution resume or are they interleaved with normal execution? Also may I ask how

Re: Timer coalescing necessary?

Hi, This is slightly different for processing-time and event-time triggers. First, event-time triggers: there are two data structures, a PriorityQueue (which is implemented as a heap) of timers that is sorted by timestamp, a set of registered timers that is used for deduplication. When adding

Re: Timer coalescing necessary?

Hi Aljoscha, Could you clarify how the timer system works right now ? For example, let's say I have a function F, with 3 keys that are registered to execute at processing time T. Would Flink maintain a single internal timer at time T, then run the callback on all 3 keys when it's triggered

Re: Timer coalescing necessary?

Hi, If you have multiple timers per key, then coalescing can make sense to reduce the burden on the timer system. Coalescing them across different keys would not be possible right now. Best, Aljoscha > On 13. Oct 2017, at 06:37, Kien Truong wrote: > > Hi, > > We

Timer coalescing necessary?

Hi, We are having a streaming job where we use timers to implement key timeout for stateful functions. Should we implement coalescing logic to reduce the number of timer trigger, or it is not necessary with Flink? Best regards, Kien