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https://issues.apache.org/jira/browse/ARROW-10168?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated ARROW-10168:
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Labels: pull-request-available (was: )
> [Rust] [Parquet] Extend arrow schema conversion to projected fields
> -------------------------------------------------------------------
>
> Key: ARROW-10168
> URL: https://issues.apache.org/jira/browse/ARROW-10168
> Project: Apache Arrow
> Issue Type: Sub-task
> Components: Rust
> Affects Versions: 1.0.1
> Reporter: Neville Dipale
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> Remaining Estimate: 0h
>
> When writing Arrow data to Parquet, we serialise the schema's IPC
> representation. This schema is then read back by the Parquet reader, and used
> to preserve the array type information from the original Arrow data.
> We however do not rely on the above mechanism when reading projected columns
> from a Parquet file; i.e. if we have a file with 3 columns, but we only read
> 2 columns, we do not yet rely on the serialised arrow schema; and can thus
> lose type information.
> This behaviour was deliberately left out, as the function
> *parquet_to_arrow_schema_by_columns* does not check for the existence of
> arrow schema in the metadata.
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