[FLINK-3888] Custom Aggregator with Convergence can't be registered directly with DeltaIteration

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.2.0
• Component/s: Runtime / Task
• Assignee: Vasia Kalavri
• Reporter: Martin Liesenberg
• Created: 09/May/16 18:53
• Updated: 29/Jan/17 14:43
• Resolved: 21/Oct/16 10:37

Description

Contrary to the documentation the method to add an aggregator with a custom convergence criterion to a DeltaIteration is not exposed directly to DeltaIteration, but can only be accessed via the aggregatorRegistry.
Moreover, when registering an aggregator with a custom convergence criterion and running the program, the following exception appears in the logs:

Error: Cannot use custom convergence criterion with workset iteration. Workset iterations have implicit convergence criterion where workset is empty.
org.apache.flink.optimizer.CompilerException: Error: Cannot use custom convergence criterion with workset iteration. Workset iterations have implicit convergence criterion where workset is empty.
	at org.apache.flink.optimizer.plantranslate.JobGraphGenerator.finalizeWorksetIteration(JobGraphGenerator.java:1518)
	at org.apache.flink.optimizer.plantranslate.JobGraphGenerator.compileJobGraph(JobGraphGenerator.java:198)
	at org.apache.flink.optimizer.plantranslate.JobGraphGenerator.compileJobGraph(JobGraphGenerator.java:164)
	at org.apache.flink.test.util.TestEnvironment.execute(TestEnvironment.java:76)
	at org.apache.flink.api.java.ExecutionEnvironment.execute(ExecutionEnvironment.java:898)
	at org.apache.flink.api.java.DataSet.collect(DataSet.java:410)
	at org.apache.flink.api.java.DataSet.print(DataSet.java:1605)

The issue has been found while discussing FLINK-2926

Issue Links

• is duplicated by: FLINK-787 Custom termination criterion in delta iteration
• links to: GitHub Pull Request #2606