Aljoscha Krettek created FLINK-3315: ---------------------------------------
Summary: Fix Slot Sharing in Streaming API Key: FLINK-3315 URL: https://issues.apache.org/jira/browse/FLINK-3315 Project: Flink Issue Type: Improvement Components: Streaming Affects Versions: 1.0.0 Reporter: Aljoscha Krettek Assignee: Aljoscha Krettek Right now, the slot sharing/resource group logic is a bit "nebulous". The slot sharing group that operators are put in depends on the order in which operations are created. For example, in this case: {code} Source a = env.source() Source b = env.source() a.map().startNewResourceGroup().sink() b.map().sink() {code} We end up with two resource groups: - group 1: source a - group 2: map(), sink(), source b, map(), sink() The reason is that the slot sharing id is incremented when transforming the {{startNewResouceGroup()}} call and all operators that are transformed afterwards in graph traversal get that new slot sharing id. (There is also {{isolateResources()}} which can be used to isolate an operator.) What I propose is to remove {{startNewResourceGroup()}} and {{isolateResouces()}} and replace it with {{slotSharingGroup(String)}}. By default, operations would be in slot sharing group "default". This allows very fine grained control over what operators end up in which slot sharing group. For example, I could have this topology: {code} Source a = env.source().slotSharingGroup("sources") Source b = env.source().slotSharingGroup("sources") a.map().slotSharingGroup("heavy a").sink().slotSharingGroup("sinks") b.map().slotSharingGroup("heavy b").sink().slotSharingGroup("sinks") {code} Which would isolate the lightweight sources and sinks in a group and put heavy operations inside their own slot groups. This is a bit more low level than the previous API and requires more calls than a simple {{startNewResourceGroup()}} but I think not many people would use this feature and this design makes it very clear what operations end up in the same group. -- This message was sent by Atlassian JIRA (v6.3.4#6332)