[HIVE-22903] Vectorized row_number() resets the row number after one batch in case of constant expression in partition clause

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.0.0
• Fix Version/s: 4.0.0-alpha-1
• Component/s: UDF, Vectorization
• Labels: pull-request-available
• Assignee: Shubham Chaurasia
• Reporter: Shubham Chaurasia
• Created: 18/Feb/20 14:48
• Updated: 17/Nov/22 08:50
• Resolved: 02/Mar/20 05:36

Description

Vectorized row number implementation resets the row number when constant expression is passed in partition clause.

Repro Query

select row_number() over(partition by 1) r1, t from over10k_n8;

Or

select row_number() over() r1, t from over10k_n8;

where table over10k_n8 contains more than 1024 records.

This happens because currently in VectorPTFOperator, we reset evaluators if only partition clause is there.

    // If we are only processing a PARTITION BY, reset our evaluators.
    if (!isPartitionOrderBy) {
      groupBatches.resetEvaluators();
    }

To resolve, we should also check if the entire partition clause is a constant expression, if it is so then we should not do groupBatches.resetEvaluators()

Issue Links

• links to: GitHub Pull Request #918