[jira] [Resolved] (IMPALA-11414) Off-by-one error in Parquet late materialization

["Zoltán Borók-Nagy (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-11414?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Zoltán Borók-Nagy resolved IMPALA-11414.
----------------------------------------
    Fix Version/s: Impala 4.2.0
       Resolution: Fixed

> Off-by-one error in Parquet late materialization
> ------------------------------------------------
>
>                 Key: IMPALA-11414
>                 URL: https://issues.apache.org/jira/browse/IMPALA-11414
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Backend
>            Reporter: Zoltán Borók-Nagy
>            Assignee: Zoltán Borók-Nagy
>            Priority: Major
>             Fix For: Impala 4.2.0
>
>
> With PARQUET_LATE_MATERIALIZATION we can set the number of minimum consecutive rows that if filtered out, we avoid materialization of rows in other columns in parquet.
> E.g. if PARQUET_LATE_MATERIALIZATION is 10, and in a filtered column we find at least 10 consecutive rows that don't pass the predicates we avoid materializing the corresponding rows in the other columns.
> But due to an off-by-one error we actually only need (PARQUET_LATE_MATERIALIZATION - 1) consecutive elements. This means if we set PARQUET_LATE_MATERIALIZATION to one, then we need zero consecutive filtered out elements which leads to a crash/DCHECK. The bug is in the GetMicroBatches() algorithm when we produce the micro batches based on the selected rows.
> Setting PARQUET_LATE_MATERIALIZATION to 0 doesn't make sense so it shouldn't be allowed.



--
This message was sent by Atlassian Jira
(v8.20.10#820010)