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Gopal Vijayaraghavan updated HIVE-23541: ---------------------------------------- Component/s: Vectorization > Vectorization: Unbounded following window function start producing results > too early > ------------------------------------------------------------------------------------ > > Key: HIVE-23541 > URL: https://issues.apache.org/jira/browse/HIVE-23541 > Project: Hive > Issue Type: Bug > Components: Vectorization > Affects Versions: 4.0.0, 3.1.2 > Reporter: Gopal Vijayaraghavan > Priority: Major > > ReduceRecordSource indicates the end of group for a reducer input, whenever > the entire key changes. > ReduceRecordSource::processVectorGroup calls > reducer.setNextVectorBatchGroupStatus(/* isLastGroupBatch */ true); when the > last group is being processed. > However for PTF window functions with unbounded following, this is triggered > by the key changing and not the partition changing. > This results in the VectorPTFOperator detect a change in the sort key as a > switch of the partition key and start producing results too early. > https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/exec/vector/ptf/VectorPTFOperator.java#L399 > {code} > create temporary table test2(id STRING,name STRING,event_dt date) stored as > orc; > insert into test2 values ('100','A','2019-08-15'), ('100','A','2019-10-12'); > SELECT name, event_dt, first_value(event_dt) over (PARTITION BY name ORDER BY > event_dt desc ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT_ROW) last_event_dt > FROM test2; -- streaming FIRST_VALUE with DESCENDING > SELECT name, event_dt, last_value(event_dt) over (PARTITION BY name ORDER BY > event_dt asc ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING ) > last_event_dt FROM test2; -- non-streaming LAST_VALUE with ASCENDING > {code} > These two queries should return identical results, with the streaming version > being significantly faster than the non-streaming one, due to the lack of > buffered/spilled rows with streaming. -- This message was sent by Atlassian Jira (v8.3.4#803005)