[FLINK-27944] IO metrics collision happens if a task has union inputs

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.15.0
• Fix Version/s: 1.17.0, 1.16.1, 1.15.4
• Component/s: Runtime / Metrics
• Labels: pull-request-available stale-assigned
• Assignee: Weijie Guo
• Reporter: Zhu Zhu
• Created: 07/Jun/22 17:03
• Updated: 01/Dec/22 16:01
• Resolved: 01/Dec/22 16:01

Description

When a task has union inputs, some IO metrics(numBytesIn* and numBuffersIn*) of the different inputs may collide and failed to be registered.

 

The problem can be reproduced with a simple job like:

DataStream<String> source1 = env.fromElements("abc");
DataStream<String> source2 = env.fromElements("123");
source1.union(source2).print();

 

Logs of collisions:

2022-06-08 00:59:01,629 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBytesInLocal'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0, Shuffle, Netty, Input]
2022-06-08 00:59:01,629 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBytesInLocalPerSecond'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0, Shuffle, Netty, Input]
2022-06-08 00:59:01,629 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBytesInLocal'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0]
2022-06-08 00:59:01,629 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBytesInLocalPerSecond'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBytesInRemote'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0, Shuffle, Netty, Input]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBytesInRemotePerSecond'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0, Shuffle, Netty, Input]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBytesInRemote'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBytesInRemotePerSecond'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBuffersInLocal'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0, Shuffle, Netty, Input]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBuffersInLocalPerSecond'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0, Shuffle, Netty, Input]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBuffersInLocal'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBuffersInLocalPerSecond'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBuffersInRemote'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0, Shuffle, Netty, Input]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBuffersInRemotePerSecond'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0, Shuffle, Netty, Input]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBuffersInRemote'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0]
2022-06-08 00:59:01,630 WARN  org.apache.flink.metrics.MetricGroup                         [] - Name collision: Group already contains a Metric with the name 'numBuffersInRemotePerSecond'. Metric will not be reported.[, taskmanager, fa9f270e-e904-4f69-8227-8d6e26e1be62, WordCount, Sink: Print to Std. Out, 0]

Issue Links

• links to: GitHub Pull Request #20033
• links to: GitHub Pull Request #21437