[jira] [Commented] (OAK-5186) ChangeSetFIlterImpl: support many includePaths by filtering for 1st path name

["Stefan Egli (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/OAK-5186?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15705462#comment-15705462 ] 

Stefan Egli commented on OAK-5186:
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Note that this problem is mostly relevant if the include paths contain globs - as otherwise it's just string comparison, which is cheaper (even though, also for large sets of include paths _without_ globs having a graph and even such a first-level-name optimization could be benefitial)

> ChangeSetFIlterImpl: support many includePaths by filtering for 1st path name
> -----------------------------------------------------------------------------
>
>                 Key: OAK-5186
>                 URL: https://issues.apache.org/jira/browse/OAK-5186
>             Project: Jackrabbit Oak
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 1.5.14
>            Reporter: Stefan Egli
>             Fix For: 1.6
>
>         Attachments: OAK-5186.patch
>
>
> When there is a large number of include paths in the ChangeSetFilterImpl and combine that with a large-ish ChangeSet (many paths) then the comparison becomes expensive, as there is a loop with each ChangeSet-path, then looping through each include path. Basically an {{O(n*m)}}.
> A probably ideal solution would be to implement a tree with the tree items be the path elements. And have two sets of trees: the filter one and the ChangeSet one.
> A simpler and perhaps 'good enough' solution could be to just look at the first level name of both the filter include paths: if a ChangeSet path's first level name is not in that set, then it can't be included. That would allow to skip the pattern comparison (which is slower even though it is a compiled {{Pattern}}).



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