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https://issues.apache.org/jira/browse/UIMA-2434?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13419772#comment-13419772
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Richard Eckart de Castilho commented on UIMA-2434:
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+1 for bulk removal. FSIterators don't like it when feature structures are
removed from the CAS while iterating over it, so we usually collect all FS to
remove in a list and bulk-remove them in the end.
> Feature structure removal from sorted index is very slow
> --------------------------------------------------------
>
> Key: UIMA-2434
> URL: https://issues.apache.org/jira/browse/UIMA-2434
> Project: UIMA
> Issue Type: Improvement
> Components: Core Java Framework
> Affects Versions: 2.3.1SDK
> Reporter: Mikhail Sogrin
>
> Removal of feature structures from sorted indexes (e.g. default index) is
> very slow. FSIntArrayIndex.remove() method performs two operations: linear
> search in the array until the given FS is found, followed by the shift of
> elements to the end of this array by one position to the left.
> If many annotations (millions and more) are being deleted at once, this
> operation gets very very slow - much slower than adding these annotations in
> the first place. It seems to require O(N^2) time to remove N annotations.
> One item is the linear search, which can be replaced by the binary search
> method, which is already implemented in the same class.
> Second, array copy can be done with Java built-in method instead of a custom
> loop.
> Ideally, a method for bulk removal of a collection of annotations would have
> been the most efficient, for example a method to remove all annotations of a
> given type.
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