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From "Chuck Williams (JIRA)" <>
Subject [jira] Updated: (LUCENE-709) [PATCH] Enable application-level management of IndexWriter.ramDirectory size
Date Wed, 22 Nov 2006 00:51:03 GMT
     [ ]

Chuck Williams updated LUCENE-709:

    Attachment: ramDirSizeManagement.patch

This one should be golden as it addresses all the issues that have been raised and I believe
the syncrhonization is fairly well optimized.

Size is now computed based on buffer size, and so is a more accurate accounting of actual
memory usage.

I've added all the various checking and FileNotFoundExceptions that Doug suggested.

I've also changed RamFile.buffers to an ArrayList per Yonik's last suggestion.  This is probably
better than cosmetic since it does allow some unnecessary syncrhonization to be eliminated.

Unfortunately, my local Lucene differs now fairly substantially from the head -- wish you
guys would commit more of my patches so merging wasn't so difficult :-) -- so I'm not using
the version submitted here, but I did merge it into the head carefully and all tests pass,
including the new RAMDIrectory tests specifically for the functionality this patch provides.

> [PATCH] Enable application-level management of IndexWriter.ramDirectory size
> ----------------------------------------------------------------------------
>                 Key: LUCENE-709
>                 URL:
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: Index
>    Affects Versions: 2.0.1
>         Environment: All
>            Reporter: Chuck Williams
>         Attachments: ramdir.patch, ramdir.patch, ramDirSizeManagement.patch, ramDirSizeManagement.patch,
ramDirSizeManagement.patch, ramDirSizeManagement.patch
> IndexWriter currently only supports bounding of in the in-memory index cache using maxBufferedDocs,
which limits it to a fixed number of documents.  When document sizes vary substantially, especially
when documents cannot be truncated, this leads either to inefficiencies from a too-small value
or OutOfMemoryErrors from a too large value.
> This simple patch exposes IndexWriter.flushRamSegments(), and provides access to size
information about IndexWriter.ramDirectory so that an application can manage this based on
total number of bytes consumed by the in-memory cache, thereby allow a larger number of smaller
documents or a smaller number of larger documents.  This can lead to much better performance
while elimianting the possibility of OutOfMemoryErrors.
> The actual job of managing to a size constraint, or any other constraint, is left up
the applicatation.
> The addition of synchronized to flushRamSegments() is only for safety of an external
call.  It has no significant effect on internal calls since they all come from a sychronized

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