java - 无法在基于 EC2 的 Cassandra 后端获取写锁

Question

我已经部署了Cassandra 3.11.1在 EC2实例并使用 JanusGraph 从我的机器连接到它Java API。出于测试目的，该实例允许所有入站和出站 TCP 连接。

在 cassandra.yaml 文件中，我配置了以下值，如下所示:

• listen_address:私有(private) EC2 地址
• broadcast_address:公共(public) EC2 地址
• 种子:公共(public) EC2 地址
• start_rpc:true
• rpc_address:私有(private) EC2 地址
• endpoint_snitch:Ec2MultiRegionSnitch

请注意，当我想使用公共(public) EC2 地址作为 rpc_address 时，Cassandra 启动失败并显示以下消息:

Failed to bind port 9042 on <public EC2 address>

最后，我尝试连接到图表，添加顶点并提交。

JanusGraph graph = JanusGraphFactory.build()
        .set("storage.backend", "cassandra")
        .set("storage.hostname", "<public EC2 address>")
        .set("storage.cassandra.keyspace", "debug")
        .set("storage.batch-loading", false)

        .set("query.force-index", false)
        .set("query.fast-property", true)

        .set("cache.db-cache", true)
        .set("schema.default", "default")

        .set("index.search.backend", "elasticsearch")
        .set("index.search.hostname", "127.0.0.1")
        .set("index.search.elasticsearch.interface", "REST_CLIENT")
        .open();

graph.addVertex("myLabel");
graph.tx().commit();

提交失败并出现以下错误:

09:41:53.297 [main] ERROR o.j.g.database.StandardJanusGraph - Could not commit transaction [1] due to exception
org.janusgraph.diskstorage.locking.TemporaryLockingException: Temporary locking failure
    at org.janusgraph.diskstorage.locking.AbstractLocker.writeLock(AbstractLocker.java:309) ~[janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.diskstorage.locking.consistentkey.ExpectedValueCheckingStore.acquireLock(ExpectedValueCheckingStore.java:103) ~[janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.diskstorage.keycolumnvalue.KCVSProxy.acquireLock(KCVSProxy.java:52) ~[janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.diskstorage.BackendTransaction.acquireIndexLock(BackendTransaction.java:256) ~[janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.graphdb.database.StandardJanusGraph.prepareCommit(StandardJanusGraph.java:572) ~[janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.graphdb.database.StandardJanusGraph.commit(StandardJanusGraph.java:702) ~[janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.commit(StandardJanusGraphTx.java:1374) [janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.graphdb.tinkerpop.JanusGraphBlueprintsGraph$GraphTransaction.doCommit(JanusGraphBlueprintsGraph.java:272) [janusgraph-core-0.2.0.jar:na]
    at org.apache.tinkerpop.gremlin.structure.util.AbstractTransaction.commit(AbstractTransaction.java:105) [gremlin-core-3.2.6.jar:3.2.6]
    at engineering.divine.core.test.ConnectionTest.test(ConnectionTest.java:29) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_45]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_45]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_45]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_45]
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) [junit-4.12.jar:4.12]
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) [junit-4.12.jar:4.12]
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) [junit-4.12.jar:4.12]
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) [junit-4.12.jar:4.12]
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) [.cp/:na]
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) [.cp/:na]
Caused by: org.janusgraph.diskstorage.TemporaryBackendException: Lock write retry count exceeded
    at org.janusgraph.diskstorage.locking.consistentkey.ConsistentKeyLocker.writeSingleLock(ConsistentKeyLocker.java:341) ~[janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.diskstorage.locking.consistentkey.ConsistentKeyLocker.writeSingleLock(ConsistentKeyLocker.java:125) ~[janusgraph-core-0.2.0.jar:na]
    at org.janusgraph.diskstorage.locking.AbstractLocker.writeLock(AbstractLocker.java:304) ~[janusgraph-core-0.2.0.jar:na]
    ... 32 common frames omitted

如果您能指出可能出现的问题，我将不胜感激。

Answer 1

我的本​​地计算机和 EC2 实例之间的网络延迟实际上太高，无法及时获取锁定。增加storage.lock.wait-time从 100 毫秒到 1 秒解决了问题。