Hi Roy,

Nice to see you back here, still going strong!

I guess the TraversalVertexProgram used for OLAP traversals is not well suited to your use case. You must realize that 200 stages in an OLAP traversal is a fairly extreme. I assume you edge count is 100 million and not 100. So, the number of paths between two vertices could easily explode and the storage of associated java objects (Traversers in the stacktrace) could grow beyond 80 Gb.

It would be relatively easy to write your own VertexProgram for this simple traversal (you can take the ConnectedComponentVertexProgram as an example). See also the explanation in the corresponding recipe. This will give you far more control over data structures and their memory usage.

Best wishes,    Marc

Op zaterdag 2 januari 2021 om 06:53:08 UTC+1 schreef Roy Yu:

The graph has 100 million vertices and 100 edges

Graph data is saved at HBase Table: MyHBaseTable.

The size of MyHBaseTable is 16.2GB:

root@~$ hdfs dfs -du -h /apps/hbase/data/data/default/

16.2 G   32.4 G   /apps/hbase/data/data/default/MyHBaseTable

MyHBaseTable has 190 regions, the edge data (HBase column family e ) of every region is less than 100MB (one spark task processes one region, in order to avoid spark OOM during loading region data, I use HBaseAdmin to split HBase region to make sure the edges data (HBase column family e ) of every region is less than 100MB) . Below the size of region 077288f4be4c439443bb45b0c2369d5b is more than 100MB because it has index data.

root@~$ hdfs dfs -du -h /apps/hbase/data/data/default/MyHBaseTable

3.8 K    7.6 K    /apps/hbase/data/data/default/MyHBaseTable/.tabledesc

0        0        /apps/hbase/data/data/default/MyHBaseTable/.tmp

78.3 M   156.7 M  /apps/hbase/data/data/default/MyHBaseTable/007e9dbf74f5d35862b68d6434f1d6f2

92.2 M   184.3 M  /apps/hbase/data/data/default/MyHBaseTable/077288f4be4c439443bb45b0c2369d5b

102.4 M  204.8 M  /apps/hbase/data/data/default/MyHBaseTable/0782782071e4a7f2d17800d4a0989a7f

50.6 M   101.3 M  /apps/hbase/data/data/default/MyHBaseTable/07e795022e56a969ede48c9c23fbbc7c

50.6 M   101.3 M  /apps/hbase/data/data/default/MyHBaseTable/084e54e61bbcfc2decd14dcbac55bc50

99.7 M   199.4 M  /apps/hbase/data/data/default/MyHBaseTable/0a85ae356b19c605d9a32b9bf513bcbb

431.3 M  862.6 M  /apps/hbase/data/data/default/MyHBaseTable/0b024c812acfa6efaa40e1cca232e192

5.0 K    10.1 K   /apps/hbase/data/data/default/MyHBaseTable/0c2d8e3a6daaa8ab30c399783e343890

...

the properties of the graph:

gremlin.graph=org.janusgraph.core.JanusGraphFactory

cluster.max-partitions = 16

storage.backend=hbase

storage.hbase.table=MyHBaseTable

storage.hbase.ext.zookeeper.znode.parent=/hbase-unsecure

schema.default=none

storage.hostname=master001,master002,master003

storage.port=2181

storage.hbase.region-count=64

storage.write-time=1000000

storage.read-time=100000

ids.block-size=200000

ids.renew-timeout=600000

ids.renew-percentage=0.4

ids.authority.conflict-avoidance-mode=GLOBAL_AUTO

index.search.backend=elasticsearch

index.search.hostname=es001,es002,es003

index.search.elasticsearch.create.ext.index.number_of_shards=15

index.search.elasticsearch.create.ext.index.refresh_interval=-1

index.search.elasticsearch.create.ext.index.translog.sync_interval=5000s

index.search.elasticsearch.create.ext.index.translog.durability=async

index.search.elasticsearch.create.ext.index.number_of_replicas=0

index.search.elasticsearch.create.ext.index.shard.check_on_startup=false

the schema of the graph:

def defineSchema(graph) {

    m = graph.openManagement()

        node = m.makeVertexLabel("node").make()

        relation = m.makeEdgeLabel("relation").make()

        obj_type_value = m.makePropertyKey("obj_type_value").dataType(String.class).make()

    // edge props

        start_time = m.makePropertyKey("start_time").dataType(Date.class).make()

        end_time = m.makePropertyKey("end_time").dataType(Date.class).make()

        count = m.makePropertyKey("count").dataType(Integer.class).make()

        rel_type = m.makePropertyKey("rel_type").dataType(String.class).make()

    //index

        m.buildIndex("MyHBaseTable_obj_type_value_Index", Vertex.class).addKey(obj_type_value).unique().buildCompositeIndex()

        m.buildIndex("MyHBaseTable_rel_type_index", Edge.class).addKey(rel_type).buildCompositeIndex()

        m.buildIndex("MyHBaseTable_count_index", Edge.class).addKey(count).buildMixedIndex("search")

        m.buildIndex("MyHBaseTable_start_time_index", Edge.class).addKey(start_time).buildMixedIndex("search")

        m.buildIndex("MyHBaseTable_end_time_index", Edge.class).addKey(end_time).buildMixedIndex("search")

    m.commit()

}

the Gremlin I use to find all paths between 2 vertices:

import org.apache.tinkerpop.gremlin.spark.process.computer.SparkGraphComputer;

import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.__;

import org.apache.tinkerpop.gremlin.process.traversal.P;

def executeScript(graph){

    traversal = graph.traversal().withComputer(SparkGraphComputer.class);

    return traversal.V(624453904).repeat(__.both().simplePath()).until(__.hasId(192204064).or().loops().is(200)).hasId(192204064).path().dedup().limit(1000).toList()

    //return traversal.V().where(__.outE().count().is(P.gte(50000))).id().toList()

};

The OLAP spark graph conf:

gremlin.graph=org.apache.tinkerpop.gremlin.hadoop.structure.HadoopGraph

gremlin.hadoop.graphReader=org.janusgraph.hadoop.formats.hbase.HBaseInputFormat

gremlin.hadoop.graphWriter=org.apache.tinkerpop.gremlin.hadoop.structure.io.gryo.GryoOutputFormat

gremlin.hadoop.jarsInDistributedCache=true

gremlin.hadoop.inputLocation=none

gremlin.hadoop.outputLocation=output

gremlin.spark.graphStorageLevel=DISK_ONLY

gremlin.spark.persistStorageLevel=DISK_ONLY

####################################

# JanusGraph HBase InputFormat configuration

####################################

janusgraphmr.ioformat.conf.storage.backend=hbase

janusgraphmr.ioformat.conf.storage.hostname=master002,master003,master001

janusgraphmr.ioformat.conf.storage.hbase.table=MyHBaseTable

janusgraphmr.ioformat.conf.storage.hbase.ext.zookeeper.znode.parent=/hbase-unsecure

####################################

# SparkGraphComputer Configuration #

####################################

spark.master=yarn

spark.submit.deployMode=client

spark.yarn.jars=hdfs://GRAPHOLAP/user/spark/jars/*.jar

# the Spark YARN ApplicationManager needs this to resolve classpath it sends to the executors

spark.yarn.appMasterEnv.JAVA_HOME=/usr/local/jdk1.8.0_191/

spark.yarn.appMasterEnv.HADOOP_CONF_DIR=/usr/hdp/3.1.4.0-315/hadoop/conf

spark.yarn.am.extraJavaOptions=-Diop.version=3.1.4.0-315 -Djava.library.path=/usr/hdp/current/hadoop-client/lib/native

spark.executor.memoryOverhead=5G

spark.driver.extraJavaOptions=-Diop.version=3.1.4.0-315 -Djava.library.path=/usr/hdp/current/hadoop-client/lib/native

# the Spark Executors (on the work nodes) needs this to resolve classpath to run Spark tasks

spark.executorEnv.JAVA_HOME=/usr/local/jdk1.8.0_191/

#spark.executorEnv.HADOOP_CONF_DIR=/usr/hdp/3.1.4.0-315/hadoop/conf

spark.executor.extraJavaOptions=-XX:+UseG1GC -XX:MaxGCPauseMillis=500 -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCDateStamps -Xloggc:/mnt/data_1/log/spark2/gc-spark%p.log

spark.executor.cores=1

spark.executor.memory=80G

spark.executor.instances=3

spark.executor.extraClassPath=/etc/hadoop/conf:/usr/spark/jars:/usr/hdp/current/hbase-client/lib:/usr/janusgraph/0.4.0/lib

spark.serializer=org.apache.spark.serializer.KryoSerializer

spark.network.timeout=1000000

spark.rpc.askTimeout=1000000

spark.shuffle.service.enabled=true

spark.shuffle.service.port=7447

spark.maxRemoteBlockSizeFetchToMem=10485760

spark.memory.useLegacyMode=true

spark.shuffle.memoryFraction=0.1

spark.storage.memoryFraction=0.1

spark.memory.fraction=0.1

spark.memory.storageFraction=0.1

spark.shuffle.accurateBlockThreshold=1048576

The spark job failed at stage 50 :

20/12/30 01:53:00 ERROR executor.Executor: Exception in task 40.0 in stage 50.0 (TID 192084)

java.lang.OutOfMemoryError: Java heap space

        at sun.reflect.generics.repository.ClassRepository.getSuperInterfaces(ClassRepository.java:114)

        at java.lang.Class.getGenericInterfaces(Class.java:913)

        at java.util.HashMap.comparableClassFor(HashMap.java:351)

        at java.util.HashMap$TreeNode.treeify(HashMap.java:1932)

        at java.util.HashMap.treeifyBin(HashMap.java:772)

        at java.util.HashMap.putVal(HashMap.java:644)

        at java.util.HashMap.put(HashMap.java:612)

        at java.util.Collections$SynchronizedMap.put(Collections.java:2588)

        at org.apache.tinkerpop.gremlin.process.traversal.traverser.util.TraverserSet.add(TraverserSet.java:90)

        at org.apache.tinkerpop.gremlin.process.computer.traversal.WorkerExecutor.lambda$drainStep$4(WorkerExecutor.java:232)

        at org.apache.tinkerpop.gremlin.process.computer.traversal.WorkerExecutor$$Lambda$86/877696627.accept(Unknown Source)

        at java.util.Iterator.forEachRemaining(Iterator.java:116)

        at org.apache.tinkerpop.gremlin.process.computer.traversal.WorkerExecutor.drainStep(WorkerExecutor.java:221)

        at org.apache.tinkerpop.gremlin.process.computer.traversal.WorkerExecutor.execute(WorkerExecutor.java:151)

        at org.apache.tinkerpop.gremlin.process.computer.traversal.TraversalVertexProgram.execute(TraversalVertexProgram.java:307)

        at org.apache.tinkerpop.gremlin.spark.process.computer.SparkExecutor.lambda$null$4(SparkExecutor.java:118)

        at org.apache.tinkerpop.gremlin.spark.process.computer.SparkExecutor$$Lambda$72/1209554928.apply(Unknown Source)

        at org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils$3.next(IteratorUtils.java:247)

        at scala.collection.convert.Wrappers$JIteratorWrapper.next(Wrappers.scala:43)

        at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala:463)

        at scala.collection.Iterator$$anon$12.hasNext(Iterator.scala:440)

From the log it seems there is too much data even the 80G executor heap is not enough. 

Anybody who can help me ?  Anybody who has idea to find all the paths between 2 vertices upon large graph?