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https://issues.apache.org/jira/browse/PARQUET-2160?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17555082#comment-17555082
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Yujiang Zhong commented on PARQUET-2160:
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[~shangxinli] [~dongjoon] Can you please take a look at this?
> Close decompression stream to free off-heap memory in time
> ----------------------------------------------------------
>
> Key: PARQUET-2160
> URL: https://issues.apache.org/jira/browse/PARQUET-2160
> Project: Parquet
> Issue Type: Improvement
> Environment: Spark 3.1.2 + Iceberg 0.12 + Parquet 1.12.3 + zstd-jni
> 1.4.9.1 + glibc
> Reporter: Yujiang Zhong
> Priority: Major
>
> The decompressed stream now relies on the JVM GC to close. When reading
> parquet in zstd compressed format, sometimes I ran into OOM cause high
> off-heap usage. I think the reason is that the GC is not timely and causes
> off-heap memory fragmentation. I had to set lower MALLOC_TRIM_THRESHOLD_ to
> make glibc give back memory to system quickly. There is a
> [thread|[https://apache-iceberg.slack.com/archives/C025PH0G1D4/p1650928750269869?thread_ts=1650927062.590789&cid=C025PH0G1D4]]
> of this zstd parquet issus in Iceberg community slack: some people had the
> same problem.
> I think we can close decompressed stream mannually in time to solve this
> problem:
>
> InputStream is = codec.createInputStream(bytes.toInputStream(), decompressor);
> decompressed = BytesInput.from(is, uncompressedSize);
> ->
> InputStream is = codec.createInputStream(bytes.toInputStream(), decompressor);
> decompressed = BytesInput.{_}copy{_}(BytesInput.{_}from{_}(is,
> uncompressedSize));
> is.close();
>
> After I made this change to decompress, I found off-heap memory is
> significantly reduced (with same query on same data).
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