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https://issues.apache.org/jira/browse/TINKERPOP-2490?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17247711#comment-17247711
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ASF GitHub Bot commented on TINKERPOP-2490:
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junshiguo opened a new pull request #1370:
URL: https://github.com/apache/tinkerpop/pull/1370
https://issues.apache.org/jira/browse/TINKERPOP-2490
In FilterStep, the processNextStart() method will first retrieve next
traverser and then apply filtering logic. But for RangleGlobalStep, if high
limit is already hit, there will be no need to get next traverser.
e.g. g.V().limit(1). This query will touch 2 vertices although only 1 vertex
will be returned.
This PR added high limit check before retrieving next traverser for
filtering. Functionality is not affected, but we can expect better performance
if getting next traverser is heavy.
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> RangeGlobalStep touches next traverser when high limit is already hit
> ---------------------------------------------------------------------
>
> Key: TINKERPOP-2490
> URL: https://issues.apache.org/jira/browse/TINKERPOP-2490
> Project: TinkerPop
> Issue Type: Bug
> Components: process
> Affects Versions: 3.4.8
> Reporter: Guo Junshi
> Priority: Major
>
> In FilterStep, the processNextStart() method will first retrieve next
> traverser and then apply filtering logic. But for RangleGlobalStep, if high
> limit is already hit, there will be no need to get next traverser.
> {code:java}
> @Override
> protected Traverser.Admin<S> processNextStart() {
> while (true) {
> final Traverser.Admin<S> traverser = this.starts.next();
> if (this.filter(traverser))
> return traverser;
> }
> }
> {code}
> An example would be limit step: g.V().limit(1). This query will touch 2
> vertices although only 1 vertex will be returned.
> This extra data loading will cause performance defects if DB data loading is
> involved. It is not a functionality bug, but for better performance, we'd
> better check high range limit first before touching next traversal.
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