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Posted to dev@parquet.apache.org by "Wes McKinney (JIRA)" <ji...@apache.org> on 2016/02/01 20:58:40 UTC

[jira] [Assigned] (PARQUET-478) Reassembly algorithms for nested in-memory columnar memory layout

     [ https://issues.apache.org/jira/browse/PARQUET-478?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Wes McKinney reassigned PARQUET-478:
------------------------------------

    Assignee: Wes McKinney

> Reassembly algorithms for nested in-memory columnar memory layout
> -----------------------------------------------------------------
>
>                 Key: PARQUET-478
>                 URL: https://issues.apache.org/jira/browse/PARQUET-478
>             Project: Parquet
>          Issue Type: New Feature
>          Components: parquet-cpp
>            Reporter: Wes McKinney
>            Assignee: Wes McKinney
>
> I plan to use parquet-cpp primarily in conjunction with columnar data structures. 
> Specifically, this requires in the interpretation of repetition / definition levels:
> * Computing null bits / bytes for each logical level of nested tree (group, array, primitive leaf)
> * Computing implied array sizes for each repeated group (according to 1, 2, or 3-level array encoding)
> The results of this reconstruction will be simply C arrays accompanied by the parquet-cpp logical schema; this way we can make it easy to adapt to different in-memory columnar memory schemes. 
> As far as implementation, it would make sense to proceed first with functional unit tests of the reassembly algorithms using repetition / definition levels declared in the test suite as C++ vectors -- otherwise it's going to be too tedious trying to produce valid Parquet test data files which explore all of the different edge cases.
> Several other teams (Spark, Drill, Parquet-Java) are currently working on related efforts along these lines, so we can engage when appropriate to collaborate on algorithms and nuances of this approach to avoid unnecessary code churn / bugs. 



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