[jira] [Commented] (PARQUET-118) Provide option to use on-heap buffers for Snappy compression/decompression

["Julien Le Dem (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PARQUET-118?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14190636#comment-14190636 ] 

Julien Le Dem commented on PARQUET-118:
---------------------------------------

Hello Patrick,
Feel free to propose a pull request for this.
I'd be happy to review.
CC [~nongli]

> Provide option to use on-heap buffers for Snappy compression/decompression
> --------------------------------------------------------------------------
>
>                 Key: PARQUET-118
>                 URL: https://issues.apache.org/jira/browse/PARQUET-118
>             Project: Parquet
>          Issue Type: Improvement
>          Components: parquet-mr
>    Affects Versions: 1.6.0rc2
>            Reporter: Patrick Wendell
>
> The current code uses direct off-heap buffers for decompression. If many decompressors are instantiated across multiple threads, and/or the objects being decompressed are large, this can lead to a huge amount of off-heap allocation by the JVM. This can be exacerbated if overall, there is not heap contention, since no GC will be performed to reclaim the space used by these buffers.
> It would be nice if there was a flag we cold use to simply allocate on-heap buffers here:
> https://github.com/apache/incubator-parquet-mr/blob/master/parquet-hadoop/src/main/java/parquet/hadoop/codec/SnappyDecompressor.java#L28
> We ran into an issue today where these buffers totaled a very large amount of storage and caused our Java processes (running within containers) to be terminated by the kernel OOM-killer.



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