[jira] [Resolved] (PARQUET-1370) [C++] Read consecutive column chunks in a single scan

["Wes McKinney (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PARQUET-1370?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Wes McKinney resolved PARQUET-1370.
-----------------------------------
    Resolution: Not A Problem

The way to address this here is to use the buffered read option 

https://github.com/apache/arrow/blob/master/cpp/src/parquet/properties.h#L58

This isn't exposed in Python for some reason, so I opened

https://issues.apache.org/jira/browse/ARROW-6253

> [C++] Read consecutive column chunks in a single scan
> -----------------------------------------------------
>
>                 Key: PARQUET-1370
>                 URL: https://issues.apache.org/jira/browse/PARQUET-1370
>             Project: Parquet
>          Issue Type: Improvement
>          Components: parquet-cpp
>            Reporter: Robbie Gruener
>            Priority: Major
>             Fix For: cpp-1.6.0
>
>
> Currently parquet-cpp calls for a filesystem scan with every single data page see [https://github.com/apache/parquet-cpp/blob/a0d1669cf67b055cd7b724dea04886a0ded53c8f/src/parquet/column_reader.cc#L181]
> For remote filesystems this can be very inefficient when reading many small columns. The java implementation already does this and will read consecutive column chunks (and the resulting pages) in a single scan see [https://github.com/apache/parquet-mr/blob/master/parquet-hadoop/src/main/java/org/apache/parquet/hadoop/ParquetFileReader.java#L786]
>  
> This might be a bit difficult to do, as it would require changing a lot of the code structure but it would certainly be valuable for workloads concerned with optimal read performance.



--
This message was sent by Atlassian JIRA
(v7.6.14#76016)