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https://issues.apache.org/jira/browse/ARROW-9790?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17180135#comment-17180135
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Andrew Lamb commented on ARROW-9790:
------------------------------------
I am pretty sure I know what the problem is, and I will have a PR up to fix
this tomorrow morning
> [Rust] [Parquet] ParquetFileArrowReader fails to decode all pages if batches
> fall exactly on row group boundaries
> -----------------------------------------------------------------------------------------------------------------
>
> Key: ARROW-9790
> URL: https://issues.apache.org/jira/browse/ARROW-9790
> Project: Apache Arrow
> Issue Type: Bug
> Reporter: Andrew Lamb
> Assignee: Andrew Lamb
> Priority: Major
> Attachments: parquet_file_arrow_reader.zip
>
>
> Basically, if the parquet input file has multiple row groups, and the
> {{batch_size}} specified to {{ParquetFileArrowReader}} falls exactly between
> them, not all rows are read
> {code}
> +-----+
> | RG1 |
> | |
> +-----+ <-- If a batch ends exactly at the end of this row group (page), RG2
> is never read
> +-----+
> | RG2 |
> | |
> +-----+
> {code}
> A reproducer is attached. 20 values should be read by the
> {{ParquetFileArrowReader}} regardless of the batch size. However, when using
> batch sizes such as {{5}} or {{3}} (which fall on a boundary between row
> groups) not all the rows are read.
> To run the reproducer, decompress the attachment
> [^parquet_file_arrow_reader.zip] and do `cargo run`
> The output is as follows:
> {code}
> wrote 20 rows in 4 row groups to /tmp/repro.parquet
> Size when reading with batch_size 100 : 20
> Size when reading with batch_size 7 : 20
> Size when reading with batch_size 5 : 5
> {code}
> The expected output is as follows (should always read 20 rows, regardless of
> the batch size):
> {code}
> wrote 20 rows in 4 row groups to /tmp/repro.parquet
> Size when reading with batch_size 100 : 20
> Size when reading with batch_size 7 : 20
> Size when reading with batch_size 5 : 20
> {code}
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