[jira] [Updated] (PARQUET-520) Add support for zero-copy InputStreams on memory-mapped files

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

     [ https://issues.apache.org/jira/browse/PARQUET-520?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Wes McKinney updated PARQUET-520:
---------------------------------
    Description: Noted this while working on PARQUET-497. If we are using a memory-mapped file, then copying data into a {{ScopedInMemoryInputStream}} as we are now is unnecessary and will yield improved performance. Perhaps this should be made a property of the {{InputStream}} (i.e. indicate whether it support zero-copy reads, and the returned buffer does not become invalid after future reads as long as the stream -- the memory map specifically in this example -- is alive)  (was: Noted this while working on PARQUET-497. If we are using a memory-mapped file, then copying data into a {{ScopedInMemoryInputStream}} as we are not is unnecessary and will yield improved performance. Perhaps this should be made a property of the {{InputStream}} (i.e. that it support zero-copy reads, and the returned buffer does not become invalid after future reads as long as the stream -- the memory map specifically in this example -- is alive))

> Add support for zero-copy InputStreams on memory-mapped files
> -------------------------------------------------------------
>
>                 Key: PARQUET-520
>                 URL: https://issues.apache.org/jira/browse/PARQUET-520
>             Project: Parquet
>          Issue Type: Improvement
>          Components: parquet-cpp
>            Reporter: Wes McKinney
>
> Noted this while working on PARQUET-497. If we are using a memory-mapped file, then copying data into a {{ScopedInMemoryInputStream}} as we are now is unnecessary and will yield improved performance. Perhaps this should be made a property of the {{InputStream}} (i.e. indicate whether it support zero-copy reads, and the returned buffer does not become invalid after future reads as long as the stream -- the memory map specifically in this example -- is alive)



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