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From "Jukka Zitting (JIRA)" <j...@apache.org>
Subject [jira] Updated: (JCR-1663) REFERENCE properties produce duplicate strings in memory
Date Thu, 26 Jun 2008 19:29:45 GMT

     [ https://issues.apache.org/jira/browse/JCR-1663?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jukka Zitting updated JCR-1663:
-------------------------------

    Attachment: JCR-1663.patch

Do you have a chance of trying out the attached patch (JCR-1663.patch)? It's a rather simple
implementation of the flyweight pattern with the added twist that it uses a fixed-size hash
table to avoid blowing up too much memory in the worst case.

The change seems to work fine (i.e. no regressions), but I don't have a good performance/memory
test suite at hand to verify whether this is worth the added complexity.

> REFERENCE properties produce duplicate strings in memory
> --------------------------------------------------------
>
>                 Key: JCR-1663
>                 URL: https://issues.apache.org/jira/browse/JCR-1663
>             Project: Jackrabbit
>          Issue Type: Improvement
>          Components: jackrabbit-core, jackrabbit-spi-commons
>    Affects Versions: 1.4, core 1.4.5
>            Reporter: Roman Puchkovskiy
>         Attachments: JCR-1663.patch
>
>
> When reference property is loaded from PM, Serializer.deserialize(NodeReferences, InputStream)
is called, which calls PropertyId.valueOf(String), which in turn calls NameFactoryImpl.create(String)
which finally splits a full property name to namespace and local name. Namespace is internalized,
but local name is not (comments say that this is done to avoid perm space overfilling).
> So, in the end, a new String instance is created for local name. This leads to considerable
memory waste when repository has a lot of nodes with REFERENCE properties.
> It seems that local name part could be internalized here too because in the most repositories
it's not allowed to create properties with arbitrary names, so the danger of perm space exhaust
does not seem to be an argument.
> As for ways to resolve this, maybe a new NameFactory implementation could be created
which would be used for properties only (and, possibly, mainly in the PropertyId.valueOf(String))
which would extend an existing NameFactoryImpl overriding its create(String) method.
> What do you think about all this?

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