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ASF GitHub Bot commented on TINKERPOP-1682: ------------------------------------------- Github user okram commented on a diff in the pull request: https://github.com/apache/tinkerpop/pull/621#discussion_r121701740 --- Diff: gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/GroupStep.java --- @@ -79,6 +79,14 @@ public void modulateBy(final Traversal.Admin<?, ?> kvTraversal) { } @Override + public void replaceLocalChild(final Traversal.Admin<?, ?> oldTraversal, final Traversal.Admin<?, ?> newTraversal) { + if (null != this.keyTraversal && this.keyTraversal.equals(oldTraversal)) + this.keyTraversal = this.integrateChild(newTraversal); + else if (null != this.valueTraversal && this.valueTraversal.equals(oldTraversal)) --- End diff -- There is going to be more complications here due to barrier handling. `GroupStep` does some pre-processing on the `valueTraversal`. https://github.com/apache/tinkerpop/blob/c5a1bdebf02538dda19fa73c26e1aa350aa8c32f/gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/GroupStep.java#L71-L75 > by-modulator optimization strategy > ---------------------------------- > > Key: TINKERPOP-1682 > URL: https://issues.apache.org/jira/browse/TINKERPOP-1682 > Project: TinkerPop > Issue Type: Improvement > Components: process > Affects Versions: 3.2.4 > Reporter: Daniel Kuppitz > Assignee: Daniel Kuppitz > > The can be a significant difference in performance depending on whether you > use {{by(id)}} or {{by(id())}}: > {noformat} > gremlin> g.V().out().in().path().by(id()).profile() > ==>Traversal Metrics > Step Count > Traversers Time (ms) % Dur > ============================================================================================================= > TinkerGraphStep(vertex,[]) 6 > 6 12.137 58.03 > VertexStep(OUT,vertex) 6 > 6 1.345 6.43 > VertexStep(IN,vertex) 12 > 12 0.861 4.12 > PathStep([[IdStep, ProfileStep]]) 12 > 12 6.570 31.42 > IdStep 36 > 36 0.452 > >TOTAL - > - 20.916 - > gremlin> g.V().out().in().path().by(id).profile() > ==>Traversal Metrics > Step Count > Traversers Time (ms) % Dur > ============================================================================================================= > TinkerGraphStep(vertex,[]) 6 > 6 0.876 11.54 > VertexStep(OUT,vertex) 6 > 6 0.714 9.40 > VertexStep(IN,vertex) 12 > 12 3.299 43.43 > PathStep([id]) 12 > 12 2.706 35.63 > >TOTAL - > - 7.596 - > {noformat} > We should have a strategy that rewrites these simple patterns. This affects > {{id()}}, {{label()}}, {{key()}}, {{value()}}, but also > {{by(values("name"))}}, which can be rewritten as {{by("name")}} -- This message was sent by Atlassian JIRA (v6.4.14#64029)