[ https://issues.apache.org/jira/browse/TINKERPOP-1254?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Ted Wilmes updated TINKERPOP-1254: ---------------------------------- Fix Version/s: 3.2.1 > Support dropping traverser path information when it is no longer needed. > ------------------------------------------------------------------------ > > Key: TINKERPOP-1254 > URL: https://issues.apache.org/jira/browse/TINKERPOP-1254 > Project: TinkerPop > Issue Type: Improvement > Components: process > Affects Versions: 3.1.1-incubating > Reporter: Marko A. Rodriguez > Assignee: Ted Wilmes > Fix For: 3.2.1 > > > The most expensive traversals (especially in OLAP) are those that can not be > "bulked." There are various reasons why two traversers at the same object can > not be bulked, but the primary reason is {{PATH}} or {{LABELED_PATH}}. That > is, when the history of the traverser is required, the probability of two > traversers having the same history is low. > A key to making traversals more efficient is to do as a much as possible to > remove historic information from a traverser so it can get bulked. How does > one do this? > {code} > g.V.as('a').out().as('b').out().where(neq('a').and().neq('b')).both().name > {code} > The {{LABELED_PATH}} of "a" and "b" are required up to the {{where()}} and at > which point, at {{both()}}, they are no longer required. It would be smart to > support: > {code} > traverser.dropLabels(Set<String>) > traverser.dropPath() > {code} > We would then, via a {{TraversalOptimizationStrategy}} insert a step between > {{where()}} and {{both()}} called {{PathPruneStep}} which would be a > {{SideEffectStep}}. The strategy would know which labels were no longer > needed (via forward lookahead) and then do: > {code} > public class PathPruneStep { > final Set<String> dropLabels = ... > final boolean dropPath = ... > public void sideEffect(final Traverser<S> traverser) { > final Traverser<S> start = this.starts.next(); > if(this.dropPath) start.dropPath(); > else start.dropLabels(labels); > } > } > {code} > Again, the more we can prune historic path data no longer needed, the higher > the probability of bulking. Think about this in terms of {{match()}}. > {code} > g.V().match( > a.out.b, > b.out.c, > c.neq.a, > c.out.b, > ).select("a") > {code} > All we need is "a" at the end. Thus, once a pattern has been passed and no > future patterns require that label, drop it! > This idea is related to TINKERPOP-331, but I don't think we should deal with > manipulating the species. Thus, I think 331 is too "low level." -- This message was sent by Atlassian JIRA (v6.3.4#6332)