Question

如果maxDepth是3代码运行正常，如果maxDepth = 4，则此代码挂起@调用td.traverse（start）（〜第38行）＆amp;然后我明白了：

线程“main”中的异常java.lang.OutOfMemoryError：Java堆空间 at java.util.Arrays.copyOf（Arrays.java:2882） at java.lang.AbstractStringBuilder.expandCapacity（AbstractStringBuilder.java:100）在java.lang.AbstractStringBuilder.append（AbstractStringBuilder.java:515）在java.lang.StringBuilder.append（StringBuilder.java:189） at com.sun.jersey.core.util.ReaderWriter.readFromAsString（ReaderWriter.java:172） at com.sun.jersey.core.util.ReaderWriter.readFromAsString（ReaderWriter.java:157） at com.sun.jersey.core.provider.AbstractMessageReaderWriterProvider.readFromAsString（AbstractMessageReaderWriterProvider.java:114） at com.sun.jersey.core.impl.provider.entity.StringProvider.readFrom（StringProvider.java:73） at com.sun.jersey.core.impl.provider.entity.StringProvider.readFrom（StringProvider.java:58） at com.sun.jersey.api.client.ClientResponse.getEntity（ClientResponse.java:552） at com.sun.jersey.api.client.ClientResponse.getEntity（ClientResponse.java:505） at org.neo4j.rest.graphdb.RequestResult.extractFrom（RequestResult.java:87） at org.neo4j.rest.graphdb.ExecutingRestRequest.post（ExecutingRestRequest.java:138） at org.neo4j.rest.graphdb.ExecutingRestAPI.traverse（ExecutingRestAPI.java:486）在org.neo4j.rest.graphdb.RestAPIFacade.traverse（RestAPIFacade.java:202）在org.neo4j.rest.graphdb.traversal.RestTraversal.traverse（RestTraversal.java:162） at com.tr.cmg.alloy.dao.psd.RelationalPathSearchDAO.executeRelationalPathSearch（RelationalPathSearchDAO.java:38）在com.tr.cmg.alloy.dao.psd.RelationalPathSearchDAO.main（RelationalPathSearchDAO.java:115）

package com.tr.cmg.alloy.dao.psd;

import java.util.ArrayList;

import org.neo4j.graphdb.Direction;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.Path;
import org.neo4j.graphdb.Relationship;
import org.neo4j.graphdb.traversal.TraversalDescription;
import org.neo4j.rest.graphdb.index.RestIndex;
import org.neo4j.rest.graphdb.traversal.RestTraversalDescription;

import com.tr.cmg.alloy.aspects.audit.DaoTierAuditAspect;
import com.tr.cmg.alloy.dao.psd.relationship.RelationType;
import com.tr.cmg.alloy.dao.support.neo4j.Neo4jDaoSupport;
import com.tr.cmg.alloy.domain.psd.NodeType;
import com.tr.cmg.alloy.services.psd.rps.RelationalPathSearch;
import com.tr.cmg.alloy.services.psd.rps.RelationalPathSearchResult;

public class RelationalPathSearchDAO extends Neo4jDaoSupport{

public RelationalPathSearchResult executeRelationalPathSearch(
        RelationalPathSearch rps) {

    RestIndex<Node> personIndex = API.getIndex(NodeType.PERSON.name());

    Node start = personIndex.get("KEY", rps.getPerson1PermId()).getSingle();
    Node end = personIndex.get("KEY", rps.getPerson2PermId()).getSingle();

    Iterable<Node> nodes = null;
    Iterable<Relationship> relationships = null;

    if (start != null && end != null) {

        TraversalDescription td = createTraversalDescription(rps);
        nodes = null;
        relationships = null;
        for (Path position : td.traverse(start)) {

            // Log audit record info
            DaoTierAuditAspect
                    .storeSqlStatement("Relational Path Neo4j Query: "
                            + rps.getPerson1PermId() + " -> "
                            + rps.getPerson2PermId());
            DaoTierAuditAspect.storeSqlParameters("");

            System.out.println(position);

            if (position.endNode().equals(end)) {
                nodes = position.nodes();
                relationships = position.relationships();
                break;
            }
        }

        if(nodes == null) {
            ArrayList<Node> x = new ArrayList<Node>();
            x.add(start);
            x.add(end);
            nodes = x;
        }
    }

    return new RelationalPathSearchResult(nodes, relationships);

}

private TraversalDescription createTraversalDescription(RelationalPathSearch rps) {

    RestTraversalDescription rtd = (RestTraversalDescription) API.createTraversalDescription();
    rtd.maxDepth(4);

    return  rtd
            .depthFirst()
            .relationships(RelationType.IsDirector, Direction.BOTH)
            .relationships(RelationType.HasGraduatedFrom, Direction.BOTH)
            .relationships(RelationType.IsOfficer, Direction.BOTH)
            .relationships(RelationType.IsUnknownOfficerDirectorAt, Direction.BOTH)
            .relationships(RelationType.IsInsiderAt, Direction.BOTH)
            .relationships(RelationType.IsEquityAnalystAt, Direction.BOTH)
            .relationships(RelationType.IsMemberOrChairmanOf, Direction.BOTH)
            .relationships(RelationType.IsChiefInvestmentOfficerAt, Direction.BOTH)
            .relationships(RelationType.IsDirectorOfResearchAt, Direction.BOTH)
            .relationships(RelationType.IsPortfolioManagerAt, Direction.BOTH)
            .relationships(RelationType.IsTraderAt, Direction.BOTH)
            .relationships(RelationType.IsEconomistAt, Direction.BOTH)
            .relationships(RelationType.IsSalesProfessionalAt, Direction.BOTH)
            .relationships(RelationType.IsStrategistAt, Direction.BOTH)
            .relationships(RelationType.IsExecutiveOfficerAt, Direction.BOTH)
            .relationships(RelationType.IsShariahSupervisoryAt, Direction.BOTH)
            .relationships(RelationType.IsNonExecutiveAt, Direction.BOTH)
            .relationships(RelationType.IsVEExecutive, Direction.BOTH)
            .relationships(RelationType.IsProvidingResearchOn, Direction.BOTH)
            .relationships(RelationType.IsAnalystAt, Direction.BOTH)
            .relationships(RelationType.IsReuterMessengerUserAt, Direction.BOTH)
            .relationships(RelationType.IsProvidingAssetClassCoverageOn, Direction.BOTH)
            .relationships(RelationType.IsSpeakingLanguageOf, Direction.BOTH)
            .relationships(RelationType.IsProvidingGeographyCoverageOf, Direction.BOTH)
            .relationships(RelationType.IsUnknownSellSideBuySideAt, Direction.BOTH)
            .relationships(RelationType.IsUnknownInsiderAt, Direction.BOTH)
            .relationships(RelationType.IsUnknownResearchAnalystAt, Direction.BOTH)
            .relationships(RelationType.IsUnknownVEExecutiveAt, Direction.BOTH)
            .relationships(RelationType.IsUnknownReutersMessengerUserAt, Direction.BOTH)
            .relationships(RelationType.IsUnknownStreetEventsUserAt, Direction.BOTH);
}

public static void main(String[] args) {

    RelationalPathSearchDAO dao = new RelationalPathSearchDAO();

    RelationalPathSearch rps = new RelationalPathSearch();
    rps.setPerson1PermId("34414591164");
    rps.setPerson2PermId("34414710307");

    RelationalPathSearchResult result = dao.executeRelationalPathSearch(rps);
    result.toJSON();

}

}

Answer 1

您需要增加JVM maximum heap memory size。

您当前的JVM内存设置是什么？

Answer 2

您可以使用“-XMX”参数增加堆空间的内存。你也可以参考这个...... How to increase heap space in memory for java

Answer 3

看起来你正试图找到两个节点之间的路径，对吧？如果您通过REST API使用allPaths或allSimplePaths算法，那么它会更快，并且需要更少的内存，因为它将是双向遍历。

不确定RestGraphDatabase是否支持它。无论哪种方式，您都可以查看http://docs.neo4j.org/chunked/stable/rest-api-graph-algos.html

Answer 4

解决了，所采用的方法将整个数据库拉入json并通过线路执行应该在db中运行的内容。

在GitHub issue中解决了这个问题。

Neo4j - Java堆空间错误 - TraversalDescription.traverse（Node）;

4 个答案: