[jira] [Resolved] (IMPALA-5004) Switch to sorting node for large TopN queries

["Sahil Takiar (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-5004?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Sahil Takiar resolved IMPALA-5004.
----------------------------------
       Resolution: Fixed
    Fix Version/s: Impala 3.1.0

> Switch to sorting node for large TopN queries
> ---------------------------------------------
>
>                 Key: IMPALA-5004
>                 URL: https://issues.apache.org/jira/browse/IMPALA-5004
>             Project: IMPALA
>          Issue Type: Improvement
>          Components: Frontend
>    Affects Versions: Impala 2.9.0
>            Reporter: Lars Volker
>            Assignee: Sahil Takiar
>            Priority: Major
>             Fix For: Impala 3.1.0
>
>
> As explained by [~tarmstrong] in IMPALA-4995:
> bq. We should also consider switching to the sort operator for large limits. This allows it to spill. The memory requirements for TopN also are problematic for large limits, since it would allocate large vectors that are untracked and also require a large amount of contiguous memory.
> There's already logic to select TopN vs. Sort: [planner/SingleNodePlanner.java#L289|https://github.com/apache/incubator-impala/blob/master/fe/src/main/java/org/apache/impala/planner/SingleNodePlanner.java#L289]



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