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https://issues.apache.org/jira/browse/IMPALA-12076?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Joe McDonnell resolved IMPALA-12076.
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Fix Version/s: Impala 4.4.0
Assignee: Joe McDonnell
Resolution: Fixed
> Potential performance improvement using ZSTD's ZSTD_decompressDCtx interface
> ----------------------------------------------------------------------------
>
> Key: IMPALA-12076
> URL: https://issues.apache.org/jira/browse/IMPALA-12076
> Project: IMPALA
> Issue Type: Improvement
> Components: Backend
> Affects Versions: Impala 4.3.0
> Reporter: Joe McDonnell
> Assignee: Joe McDonnell
> Priority: Major
> Fix For: Impala 4.4.0
>
>
> In ORC-639, they note that ZSTD's simple interface initializes the context on
> each call to ZSTD_decompress(). When calling ZSTD_decompress() many times, it
> is better to allocate the context once and use the ZSTD_decompressDCtx()
> interface to avoid the repeated initialization.
> The ZSTD code mentions that here:
>
> {noformat}
> /*= Decompression context
> * When decompressing many times,
> * it is recommended to allocate a context only once,
> * and re-use it for each successive compression operation.
> * This will make workload friendlier for system's memory.
> * Use one context per thread for parallel execution. */
> typedef struct ZSTD_DCtx_s ZSTD_DCtx;{noformat}
> We should investigate using this for decompress.h/.cc's
> ZstandardDecompressor. We already do that for the streaming decompression
> mode, but this should also apply to block decompression. Something similar is
> possible for compression as well.
>
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