issues with gremlin-server

[nsouch]

Hi folks,

I'm using ArcadeDB Server v22.9.1 and I encounter several issues.

Any query using gremlin-python (3.5.1) gives the following error:

499: The traversal source [g] for alias [g] is not configured on the server. (None)

I checked and I have these lines correctly set in gremlin-server.groovy:

globals << [graph : graph.traversal()]
globals << [g : graph.traversal()]

I also tried gremlin console (3.5.1) but got the following:

gremlin> :remote connect tinkerpop.server conf/remote-arcadedb.yaml
gremlin> :> g.V().count()
gremlin-groovy is not an available GremlinScriptEngine

Unfortunatly both without any error in the log on the arcadedb side. Any hint?
Thx in advance.

[lvca]

Please check the file gremlin-server.properties it should contain something like:

gremlin.graph=org.apache.tinkerpop.gremlin.arcadedb.structure.ArcadeGraph
gremlin.arcadedb.directory=./target/databases0/graph

That should be the path to your database.

[nsouch]

Yes, this is the content of gremlin-server.properties already.

[lvca]

Please try to replace ./target/databases0/graph with the directory where your database is located.

[nsouch]

Finally, I gave a try to v22.11.1 and got more information. When 'graph' is first created, no problem. But after a CTRL-C to stop the server and a new launch of bin\server.bat, I get the following list of errors (truncated):

(How should I properly shutdown ArcadeDB server under windows?)

$ openjdk-11.0.2_windows-x64_bin\jdk-11.0.2\bin\java -server   -XX:+HeapDumpOnOutOfMemoryError -Djava.awt.headless=true -Dfile.encoding=UTF8 -Dcom.sun.management.jmxremote=true -Dcom.sun.management.jmxremote.local.only=false -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.port=9999 -Dcom.sun.management.jmxremote.rmi.port=9998  -Darcadedb.server.plugins=GremlinServer:com.arcadedb.server.gremlin.GremlinServerPlugin   -cp "C:\Users\**************\arcadedb-22.11.1\lib\*" com.arcadedb.server.ArcadeDBServer

2022-12-10 18:46:26.021 INFO  [ArcadeDBServer]  ArcadeDB Server v22.11.1 (build d3c1dd29bbb5f102090e90b577b9d0ef57a33c2c/1670448542475/main) is starting up...
2022-12-10 18:46:26.022 INFO  [ArcadeDBServer]  Starting ArcadeDB Server with plugins [GremlinServer] ...
2022-12-10 18:46:26.036 INFO  [ArcadeDBServer]  - JMX Metrics Started...
2022-12-10 18:46:26.129 WARNI [EmbeddedDatabase]  Database 'graph' was not closed properly last time
2022-12-10 18:46:26.129 WARNI [TransactionManager]  Started recovery of database 'graph'
2022-12-10 18:46:26.159 WARNI [TransactionManager]  Recovery of database 'graph' completedGraph [graph] configured at [./config/gremlin-server.properties] could not be instantiated and will not be available in Gremlin Server.  GraphFactory message: GraphFactory could not instantiate this Graph implementation [class org.apache.tinkerpop.gremlin.arcadedb.structure.ArcadeGraph]
java.lang.RuntimeException: GraphFactory could not instantiate this Graph implementation [class org.apache.tinkerpop.gremlin.arcadedb.structure.ArcadeGraph]
        at org.apache.tinkerpop.gremlin.structure.util.GraphFactory.open(GraphFactory.java:84)
        at org.apache.tinkerpop.gremlin.structure.util.GraphFactory.open(GraphFactory.java:72)
        at org.apache.tinkerpop.gremlin.structure.util.GraphFactory.open(GraphFactory.java:106)
        at org.apache.tinkerpop.gremlin.server.util.DefaultGraphManager.addGraph(DefaultGraphManager.java:63)
        at java.base/java.util.LinkedHashMap.forEach(LinkedHashMap.java:684)
        at org.apache.tinkerpop.gremlin.server.util.DefaultGraphManager.(DefaultGraphManager.java:58)
        at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
        at org.apache.tinkerpop.gremlin.server.util.ServerGremlinExecutor.(ServerGremlinExecutor.java:86)
        at org.apache.tinkerpop.gremlin.server.GremlinServer.(GremlinServer.java:127)
        at org.apache.tinkerpop.gremlin.server.GremlinServer.(GremlinServer.java:90)
        at com.arcadedb.server.gremlin.GremlinServerPlugin.startService(GremlinServerPlugin.java:87)
        at com.arcadedb.server.ArcadeDBServer.registerPlugins(ArcadeDBServer.java:189)
        at com.arcadedb.server.ArcadeDBServer.start(ArcadeDBServer.java:134)
        at com.arcadedb.server.ArcadeDBServer.main(ArcadeDBServer.java:91)
Caused by: java.lang.reflect.InvocationTargetException
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:566)
        at org.apache.tinkerpop.gremlin.structure.util.GraphFactory.open(GraphFactory.java:80)
        ... 16 more
Caused by: com.arcadedb.exception.DatabaseOperationException: Error on creating new database instance
        at com.arcadedb.database.EmbeddedDatabase.openInternal(EmbeddedDatabase.java:1687)
        at com.arcadedb.database.EmbeddedDatabase.open(EmbeddedDatabase.java:190)
        at com.arcadedb.database.DatabaseFactory.open(DatabaseFactory.java:76)
        at com.arcadedb.database.DatabaseFactory.open(DatabaseFactory.java:68)
        at org.apache.tinkerpop.gremlin.arcadedb.structure.ArcadeGraph.(ArcadeGraph.java:96)
        at org.apache.tinkerpop.gremlin.arcadedb.structure.ArcadeGraph.open(ArcadeGraph.java:123)
        ... 21 more
Caused by: com.arcadedb.utility.LockException: Database './databases/graph' is locked by another process (path=C:\Users\*************\arcadedb-22.11.1\.\databases\graph)
        at com.arcadedb.database.EmbeddedDatabase.lockDatabase(EmbeddedDatabase.java:1533)
        at com.arcadedb.database.EmbeddedDatabase.checkForRecovery(EmbeddedDatabase.java:1626)
        at com.arcadedb.database.EmbeddedDatabase.openInternal(EmbeddedDatabase.java:1665)
        ... 26 more
Caused by: java.nio.channels.OverlappingFileLockException
        at java.base/sun.nio.ch.FileLockTable.checkList(FileLockTable.java:229)
        at java.base/sun.nio.ch.FileLockTable.add(FileLockTable.java:123)
        at java.base/sun.nio.ch.FileChannelImpl.tryLock(FileChannelImpl.java:1154)
        at java.base/java.nio.channels.FileChannel.tryLock(FileChannel.java:1165)
        at com.arcadedb.database.EmbeddedDatabase.lockDatabase(EmbeddedDatabase.java:1514)
        ... 28 more

2022-12-10 18:46:26.685 INFO  [ServerGremlinExecutor] Initialized Gremlin thread pool.  Threads in pool named with pattern gremlin-*
2022-12-10 18:46:26.702 INFO  [ServerGremlinExecutor] Initialized GremlinExecutor and preparing GremlinScriptEngines instances.WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.codehaus.groovy.reflection.CachedClass (file:/C:/Users/**************/arcadedb-22.11.1/lib/arcadedb-gremlin-22.11.1.jar) to method java.lang.Object.finalize()
WARNING: Please consider reporting this to the maintainers of org.codehaus.groovy.reflection.CachedClass
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Could not create GremlinScriptEngine for gremlin-groovy
[...etc...]

[lvca]

It looks like the old process is still locking the file. Can you please check the java process is not running?

[nsouch]

No, same with a fresh reboot.

checkForRecovery() seems to be called twice:
once with completion:

2022-12-10 18:46:26.129 WARNI [EmbeddedDatabase]  Database 'graph' was not closed properly last time
2022-12-10 18:46:26.129 WARNI [TransactionManager]  Started recovery of database 'graph'
2022-12-10 18:46:26.159 WARNI [TransactionManager]  Recovery of database 'graph' completed

and once with an exception:

Caused by: com.arcadedb.utility.LockException: Database './databases/graph' is locked by another process (path=C:\Users\*************\arcadedb-22.11.1\.\databases\graph)
        at com.arcadedb.database.EmbeddedDatabase.lockDatabase(EmbeddedDatabase.java:1533)
        at com.arcadedb.database.EmbeddedDatabase.checkForRecovery(EmbeddedDatabase.java:1626)
        at com.arcadedb.database.EmbeddedDatabase.openInternal(EmbeddedDatabase.java:1665)

Could it be an overlap? Threads?

[lvca]

I tried different things, but I can't reproduce this issue. The easiest explanation is that there must be another java server running, or the database is opened by another thread on the same JVM.

You should share the same Database instance across the entire JVM. The Database class is thread-safe.