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https://issues.apache.org/jira/browse/ARROW-10131?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Joris Van den Bossche updated ARROW-10131:
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Fix Version/s: 3.0.0
> [C++][Dataset] Lazily parse parquet metadata / statistics in
> ParquetDatasetFactory and ParquetFileFragment
> ----------------------------------------------------------------------------------------------------------
>
> Key: ARROW-10131
> URL: https://issues.apache.org/jira/browse/ARROW-10131
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++
> Reporter: Joris Van den Bossche
> Priority: Major
> Labels: dataset, dataset-dask-integration
> Fix For: 3.0.0
>
>
> Related to ARROW-9730, parsing of the statistics in parquet metadata is
> expensive, and therefore should be avoided when possible.
> For example, the {{ParquetDatasetFactory}} ({{ds.parquet_dataset()}} in
> python) parses all statistics of all files and all columns. While when doing
> a filtered read, you might only need the statistics of certain files (eg if a
> filter on a partition field already excluded many files) and certain columns
> (eg only the columns on which you are actually filtering).
> The current API is a bit all-or-nothing (both ParquetDatasetFactory, or a
> later EnsureCompleteMetadata parse all statistics, and don't allow parsing a
> subset, or only parsing the other (non-statistics) metadata, ...), so I think
> we should try to think of better abstractions.
> cc [~rjzamora] [~bkietz]
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