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https://issues.apache.org/jira/browse/IMPALA-5096?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alexander Behm updated IMPALA-5096:
-----------------------------------
Labels: parquet performance ramp-up (was: )
> Use parquet::Statistics for min/max aggregates when only a subset of scan
> columns have stats
> --------------------------------------------------------------------------------------------
>
> Key: IMPALA-5096
> URL: https://issues.apache.org/jira/browse/IMPALA-5096
> Project: IMPALA
> Issue Type: Sub-task
> Components: Backend
> Affects Versions: Impala 2.8.0
> Reporter: Alexander Behm
> Labels: parquet, performance, ramp-up
>
> If some columns do not have parquet::Statistics, then it is still possible to
> use the stats of those columns that do have them, but with more effort. For
> those columns that have stats, we can populate the scanner's template tuple
> with the stats values, and avoid scanning/materializing those columns. We
> still need to scan the columns that do not have stats.
> Also consider how the various optimizations in IMPALA-4986 will interact. For
> example,
> {code}
> select min(string_col), count(*) from parquet_table
> {code}
> Can we still safely apply any of the optimizations?
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