TransactionEventHandler在Node.setProperty（）上给出javax.transaction.SystemException [英] TransactionEventHandler gives javax.transaction.SystemException on Node.setProperty()
问题描述
我正在尝试实现一个 TransactionEventHandler ，就像在 neo4j-versioning 创建时间机器风格，版本为Neo4j数据库，现在使用Neo4j 2.x.它失败了以下无限堆栈跟踪：
javax.transaction.SystemException：TM遇到一些问题，请执行必要的操作tx recovery / restart）
在org.neo4j.kernel.impl.transaction.TxManager.assertTmOk（TxManager.java:349）
在org.neo4j.kernel.impl.transaction.TxManager.setRollbackOnly（TxManager .java：758）
在org.neo4j.kernel.TransactionEventHandlers.beforeCompletion（TransactionEventHandlers.java:120）
在org.neo4j.kernel.impl.core.TransactionEventsSyncHook.beforeCompletion（TransactionEventsSyncHook.java:68 ）
在org.neo4j.kernel.impl.transaction.TransactionImpl.doBeforeCompletion（TransactionImpl.java:368）
在org.neo4j.kernel.impl.transaction.TxManager.commit（TxManager.java:398 ）
在org.neo4j.kernel.impl.core.IsolatedTransactionTokenCreator.getOrCreate（IsolatedTransactionTokenCreator.java:61）
在org.neo4j.kernel.impl.core.TokenHolder.createToken（TokenHolder.java:114 ）
在org.neo4j.kernel.impl.co re.TokenHolder.getOrCreateId（TokenHolder.java:102）
在org.neo4j.kernel.impl.api.store.DiskLayer.propertyKeyGetOrCreateForName（DiskLayer.java:367）
在org.neo4j.kernel。 impl.api.store.CacheLayer.propertyKeyGetOrCreateForName（CacheLayer.java:370）
在org.neo4j.kernel.impl.api.StateHandlingStatementOperations.propertyKeyGetOrCreateForName（StateHandlingStatementOperations.java:939）
在org.neo4j。 kernel.impl.api.DataIntegrityValidatingStatementOperations.propertyKeyGetOrCreateForName（DataIntegrityValidatingStatementOperations.java:67）
在org.neo4j.kernel.impl.api.OperationsFacade.propertyKeyGetOrCreateForName（OperationsFacade.java:397）
在org.neo4j。 kernel.impl.core.NodeProxy.setProperty（NodeProxy.java:205）
...
这是我的测试：
@Test
public void test（）{
GraphDatabaseService graphDb = new TestGraphDatabaseFactory（）。newImpermanentDatabase（）;
Node referenceNode = null;
try（Transaction transaction = graphDb.beginTx（））{
referenceNode = graphDb.createNode（）;
transaction.success（）;
}
VersioningTransactionEventHandler versioningTransactionEventHandler = new VersioningTransactionEventHandler（referenceNode）;
graphDb.registerTransactionEventHandler（versioningTransactionEventHandler）;
try（Transaction tx = graphDb.beginTx（））{
Node node = graphDb.createNode（）;
tx.success（）;
}
graphDb.shutdown（）;
}
这是 VersioningTransactionEventHandler ：
public class VersioningTransactionEventHandler实现TransactionEventHandler< Object> {
private final Node versionDataNode;
public VersioningTransactionEventHandler（Node versionDataNode）{
this.versionDataNode = versionDataNode;
}
@Override
public Object beforeCommit（TransactionData data）throws Exception {
versionDataNode.setProperty（foo，bar）; //< - 这会导致错误
返回null;
}
@Override
public void afterCommit（TransactionData data，Object state）
{
}
@Override
public void afterRollback（TransactionData data，Object state）
{
}
}
我正在使用 org.neo4j.neo4j-2.0.1 和 org.neo4j.neo4j-kernel-2.0。 1 在我的应用程序。
为什么 setProperty（）导致此错误？我该怎么解决？
更新
$ b $由于Michael Hunger建议我在传递节点之前先做了一个
setProperty（），但现在测试静默挂起无穷远，没有任何反应。在节点上设置什么属性键值对无关紧要： ...
referenceNode = graphDb.createNode（）;
referenceNode.setProperty（foo，bar）; //< - result in hang
referenceNode.setProperty（herp，derp）; //< - 结果也挂起
...
任何线索？我只想在事务事件处理程序内部操作一个节点，就像在 1.9版本，但Neo4j 2.x没有 GraphDatabaseService＃getReferenceNode（）方法，它在那里的构造函数中传递。
我发现一个解决方法，最后一次挂起，当我打电话 setProperty（） in beforeCommit（）。似乎它只发生在非写入事务（我认为 beforeCommit（）仅在写作操作）？
所以，如果我在进行属性设置之前检查，挂起消失：
...
@Override
public Object beforeCommit（TransactionData data）throws异常{
if（containsWriteChanges（data））{
versionDataNode .setProperty（foo，bar）;
}
返回null;
}
private boolean containsWriteChanges（TransactionData data）{
return data.assignedNodeProperties（）。iterator（）。hasNext（）
|| data.assignedRelationshipProperties（）。iterator（）。hasNext（）
|| data.createdNodes（）。iterator（）。hasNext（）
|| data.createdRelationships（）。iterator（）。hasNext（）
|| data.deletedNodes（）。iterator（）。hasNext（）
|| data.deletedRelationships（）。iterator（）。hasNext（）
|| data.removedNodeProperties（）。iterator（）。hasNext（）
|| 。data.removedRelationshipProperties（）迭代（）hasNext（）;
}
...
I'm trying to implement a TransactionEventHandler like the one used in neo4j-versioning in order to create a time-machine style, versioned Neo4j database, now using Neo4j 2.x. It fails with the following infinite stack trace:
javax.transaction.SystemException: TM has encountered some problem, please perform necessary action (tx recovery/restart)
at org.neo4j.kernel.impl.transaction.TxManager.assertTmOk(TxManager.java:349)
at org.neo4j.kernel.impl.transaction.TxManager.setRollbackOnly(TxManager.java:758)
at org.neo4j.kernel.TransactionEventHandlers.beforeCompletion(TransactionEventHandlers.java:120)
at org.neo4j.kernel.impl.core.TransactionEventsSyncHook.beforeCompletion(TransactionEventsSyncHook.java:68)
at org.neo4j.kernel.impl.transaction.TransactionImpl.doBeforeCompletion(TransactionImpl.java:368)
at org.neo4j.kernel.impl.transaction.TxManager.commit(TxManager.java:398)
at org.neo4j.kernel.impl.core.IsolatedTransactionTokenCreator.getOrCreate(IsolatedTransactionTokenCreator.java:61)
at org.neo4j.kernel.impl.core.TokenHolder.createToken(TokenHolder.java:114)
at org.neo4j.kernel.impl.core.TokenHolder.getOrCreateId(TokenHolder.java:102)
at org.neo4j.kernel.impl.api.store.DiskLayer.propertyKeyGetOrCreateForName(DiskLayer.java:367)
at org.neo4j.kernel.impl.api.store.CacheLayer.propertyKeyGetOrCreateForName(CacheLayer.java:370)
at org.neo4j.kernel.impl.api.StateHandlingStatementOperations.propertyKeyGetOrCreateForName(StateHandlingStatementOperations.java:939)
at org.neo4j.kernel.impl.api.DataIntegrityValidatingStatementOperations.propertyKeyGetOrCreateForName(DataIntegrityValidatingStatementOperations.java:67)
at org.neo4j.kernel.impl.api.OperationsFacade.propertyKeyGetOrCreateForName(OperationsFacade.java:397)
at org.neo4j.kernel.impl.core.NodeProxy.setProperty(NodeProxy.java:205)
...
This is my test:
@Test
public void test() {
GraphDatabaseService graphDb = new TestGraphDatabaseFactory().newImpermanentDatabase();
Node referenceNode = null;
try (Transaction transaction = graphDb.beginTx()) {
referenceNode = graphDb.createNode();
transaction.success();
}
VersioningTransactionEventHandler versioningTransactionEventHandler = new VersioningTransactionEventHandler(referenceNode);
graphDb.registerTransactionEventHandler(versioningTransactionEventHandler);
try (Transaction tx = graphDb.beginTx()) {
Node node = graphDb.createNode();
tx.success();
}
graphDb.shutdown();
}
This is the VersioningTransactionEventHandler:
public class VersioningTransactionEventHandler implements TransactionEventHandler<Object> {
private final Node versionDataNode;
public VersioningTransactionEventHandler(Node versionDataNode) {
this.versionDataNode = versionDataNode;
}
@Override
public Object beforeCommit(TransactionData data) throws Exception {
versionDataNode.setProperty("foo", "bar"); // <- this causes the error
return null;
}
@Override
public void afterCommit(TransactionData data, Object state)
{
}
@Override
public void afterRollback(TransactionData data, Object state)
{
}
}
I'm using org.neo4j.neo4j-2.0.1 and org.neo4j.neo4j-kernel-2.0.1 in my application.
Why is the setProperty() causing this error? How can I fix it? Any clues to what may be wrong here is greatly appreciated.
Update
As Michael Hunger suggested I did a setProperty() before passing the node in, but now the test silently hangs for infinity and nothing happens. It doesn't matter what property key-value pair is set on the node:
...
referenceNode = graphDb.createNode();
referenceNode.setProperty("foo", "bar"); // <- results in hang
referenceNode.setProperty("herp", "derp"); // <- results in hang also
...
Still any clues? I just want to manipulate a node while inside the transaction event handler like it was done in the 1.9 version, but Neo4j 2.x doesn't have the GraphDatabaseService#getReferenceNode() method which is passed in the constructor there.
I found a workaround the last hang happening when I called setProperty() in beforeCommit(). It seems it only happens on non-write transactions (I thought beforeCommit() was only called on write operations)?
So then, if I check that before doing the property setting, the hanging disappears:
...
@Override
public Object beforeCommit(TransactionData data) throws Exception {
if (containsWriteChanges(data)) {
versionDataNode.setProperty("foo", "bar");
}
return null;
}
private boolean containsWriteChanges(TransactionData data) {
return data.assignedNodeProperties().iterator().hasNext()
|| data.assignedRelationshipProperties().iterator().hasNext()
|| data.createdNodes().iterator().hasNext()
|| data.createdRelationships().iterator().hasNext()
|| data.deletedNodes().iterator().hasNext()
|| data.deletedRelationships().iterator().hasNext()
|| data.removedNodeProperties().iterator().hasNext()
|| data.removedRelationshipProperties().iterator().hasNext();
}
...
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