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https://issues.apache.org/jira/browse/OAK-825?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13659552#comment-13659552
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Thomas Mueller commented on OAK-825:
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Using a NodeRev class sounds like a good solution.
The biggest performance problem I see in my tests is that MongoDB documents can
grow very large, because they are not split. I will first have a look at this
problem.
> Unnecessary performance overhead in MongoMK's calculation of keys for the
> nodeCache, nodeChildrenCache
> ------------------------------------------------------------------------------------------------------
>
> Key: OAK-825
> URL: https://issues.apache.org/jira/browse/OAK-825
> Project: Jackrabbit Oak
> Issue Type: Bug
> Components: mongomk
> Affects Versions: 0.7
> Reporter: Lukas Eder
> Attachments: MongoMK.nodeCache.png
>
>
> The key of MongoMK.nodeCache and nodeChildrenCache is currently a String,
> whose evaluation is somewhat expensive:
> {code}
> path + "@" + rev
> {code}
> In the above code, "rev.toString()" internally creates another StringBuilder
> to generate another intermediate string. The attached screenshot shows that
> around 5% of profiling time within "MongoMK.getNode()" is wasted in order to
> calculate the caching key. Other methods are also affected.
> A simple way to improve this is to reuse a single StringBuilder for the key,
> as such:
> {code}
> StringBuilder sb = new StringBuilder();
> sb.append(path);
> sb.append("@");
> rev.appendTo(sb);
> {code}
> A better way would probably be to wrap "path" and "rev" in another re-usable
> "NodeRev" object to be used instead of using two references "path" and "rev".
> The "NodeRev" object would provide appropriate equals() and hashCode()
> implementations.
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