[jira] [Updated] (IMPALA-9578) Read/write support for BINARY in Parquet

["Csaba Ringhofer (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-9578?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Csaba Ringhofer updated IMPALA-9578:
------------------------------------
    Component/s: Backend

> Read/write support for BINARY in Parquet
> ----------------------------------------
>
>                 Key: IMPALA-9578
>                 URL: https://issues.apache.org/jira/browse/IMPALA-9578
>             Project: IMPALA
>          Issue Type: Sub-task
>          Components: Backend
>            Reporter: Csaba Ringhofer
>            Priority: Major
>
> In Parquet both STRING and BINARY are stored using the same physical type, BYTE_ARRAY.
> There is a  String annotation among logical types (https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#string), which means UTF-8 encoding (and is of course ignored by Impala).
> Both reading and writing should occur the same way as with STRING.
> There is one potential difference to consider during writing: in ORC BinaryStatistics has no min/max stats (StringStatistics has them). My guess for the reason is that binary values are often very large and "random", so it is likely for the stats to need a lot of space while never being used successfully for filtering. Note that Parquet is a bit different with its per-page statistics and can be potentially need even more space for stats.



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