[jira] [Updated] (PARQUET-787) Add a size limit for heap allocations when reading

["Ryan Blue (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PARQUET-787?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ryan Blue updated PARQUET-787:
------------------------------
    Issue Type: Improvement  (was: Bug)

> Add a size limit for heap allocations when reading
> --------------------------------------------------
>
>                 Key: PARQUET-787
>                 URL: https://issues.apache.org/jira/browse/PARQUET-787
>             Project: Parquet
>          Issue Type: Improvement
>          Components: parquet-mr
>    Affects Versions: 1.9.0
>            Reporter: Ryan Blue
>            Assignee: Ryan Blue
>
> [G1GC allocates humongous objects directly in the old generation|https://www.infoq.com/articles/tuning-tips-G1-GC] to avoid unnecessary copies, which means that these allocations aren't garbage collected until a full GC runs. Humongous objects are objects that are 50% of the region size or more. Region size is at most 32MB (see the table for [region size from heap size|http://product.hubspot.com/blog/g1gc-fundamentals-lessons-from-taming-garbage-collection#Regions]).
> Parquet currently allocates a huge buffer for each contiguous group of column chunks, which in many cases is not garbage collected until a full GC. Adding a size limit for the allocation size should allow users to break row groups across multiple buffers so that buffers get collected when they have been read.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)