Nico Kruber created FLINK-20059: ----------------------------------- Summary: Outdated SQL docs on aggregate functions' merge Key: FLINK-20059 URL: https://issues.apache.org/jira/browse/FLINK-20059 Project: Flink Issue Type: Bug Components: Documentation, Table SQL / API Affects Versions: 1.11.2, 1.12.0 Reporter: Nico Kruber
In the java docs as well as the user docs, the {{merge}} method of an aggregation UDF is described as optional, e.g. {quote}Merges a group of accumulator instances into one accumulator instance. This function must be implemented for data stream session window grouping aggregates and data set grouping aggregates.{quote} However, it seems that nowadays this method is required in more cases (I stumbled on this for a HOP window in streaming): {code} StreamExecGlobalGroupAggregate.scala .needMerge(mergedAccOffset, mergedAccOnHeap, mergedAccExternalTypes) StreamExecGroupWindowAggregateBase.scala generator.needMerge(mergedAccOffset = 0, mergedAccOnHeap = false) StreamExecIncrementalGroupAggregate.scala .needMerge(mergedAccOffset, mergedAccOnHeap = true, mergedAccExternalTypes) StreamExecLocalGroupAggregate.scala .needMerge(mergedAccOffset = 0, mergedAccOnHeap = true) {code} -- This message was sent by Atlassian Jira (v8.3.4#803005)