[jira] [Comment Edited] (JENA-1414) Performance regression in Model.remove(Model m) method

["Andy Seaborne (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/JENA-1414?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16226630#comment-16226630 ] 

Andy Seaborne edited comment on JENA-1414 at 10/31/17 11:33 AM:
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See the discussion on JENA-1284.

If {{remove(Model)}} is not suitable when the argument model is persistent, then the application will need to take more direct control using {{remove(StmtIterator)}} or calls to {{removeAll}}, or even drop down to {{GraphUtil}} bulk operations.

I do not see how {{remove(Model)}} can adapt (short of extensive redesign to Jena graphs). It is better to provide the cases where {{size()}} is cheap or cached.

Possible change to javadoc of {{GraphUtil.deleteFrom(Graph, Graph}}:
{noformat}
    /**
     * Delete triples in the destination (arg 1) as given in the source (arg 2). If
     * {@code dstGraph} is a graph where {@code Graph.size()} is expensive (e.g. it is
     * persistent), then call {@link #delete(dstGraph, srcGraph.find())} instead.
     */
{noformat}



was (Author: andy.seaborne):
See the discussion on JENA-1284.

If {{remove(Model)}} is not suitable when the argument model is persistent, then the application will need to take more direct control using {{remove(StmtIterator)}} or calls to {{removeAll}}, or even drop down to {{GraphUtil}} bulk operations.

I do not see how {{remove(Model)}} can adapt (short of extensive redesign to Jena graphs). It is better to provide the cases where {{size()}} is cheap or cached.

Possible change to javadoc:
{noformat}
    /**
     * Delete triples in the destination (arg 1) as given in the source (arg 2). If
     * {@code dstGraph} is a graph where {@code Graph.size()} is expensive (e.g. it is
     * persistent), then call {@link #delete(dstGraph, srcGraph.find())} instead.
     */
{noformat}


> Performance regression in Model.remove(Model m) method
> ------------------------------------------------------
>
>                 Key: JENA-1414
>                 URL: https://issues.apache.org/jira/browse/JENA-1414
>             Project: Apache Jena
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: Jena 3.3.0, Jena 3.4.0
>            Reporter: Michał Woźniak
>
> The Model.remove(Model) works very slow on large models, as it propagates to GraphUtil.deleteFrom(Graph, Graph), which computes size of the target graph by iterating over all triples. This computation takes nearly 100% of the time of the Model.remove(Model) operation.
> It seems this commit introduced the issue: https://github.com/apache/jena/commit/781895ce64e062c7f2268a78189a777c39b92844#diff-fbb4d11dc804464f94c27e33e11b18e8
> Due to this bug deletion of a concept scheme on a large ontology may take several minutes. 



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