如何禁用或正确配置JanusGraph连接Cassandra的表压缩？

在Kubernetes环境中运行JanusGraph 1.0.0，连接Cassandra 5.0.0-jammy集群，两台Cassandra节点运行正常，但JanusGraph容器启动时抛出压缩配置相关错误。遍查Cassandra、JanusGraph及Gremlin Server文档，未找到compression.class属性的相关说明，仅找到Cassandra表压缩的相关参考。

尝试了以下多种表压缩相关配置组合，均无效：

V1

storage.cql.compression=false
storage.cql.compression-type=

V2

root.storage.cql.compression=false
root.storage.cql.compression-type=

V3

storage.cql.compression=true
storage.cql.compression-type=LZ4Compressor

V4

root.storage.cql.compression=true
root.storage.cql.compression-type=LZ4Compressor

抛出的错误 #

Caused by:
com.datastax.oss.driver.api.core.servererrors.InvalidConfigurationInQueryException:
Missing sub-option 'class' for the 'compression' option. at
com.datastax.oss.driver.api.core.servererrors.InvalidConfigurationInQueryException.copy(InvalidConfigurationInQueryException.java:52)
~[java-driver-core-4.17.0.jar:?] at
com.datastax.oss.driver.internal.core.util.concurrent.CompletableFutures.getUninterruptibly(CompletableFutures.java:149)
~[java-driver-core-4.17.0.jar:?] at
com.datastax.oss.driver.internal.core.cql.CqlRequestSyncProcessor.process(CqlRequestSyncProcessor.java:53)
~[java-driver-core-4.17.0.jar:?] at
com.datastax.oss.driver.internal.core.cql.CqlRequestSyncProcessor.process(CqlRequestSyncProcessor.java:30)
~[java-driver-core-4.17.0.jar:?] at
com.datastax.oss.driver.internal.core.session.DefaultSession.execute(DefaultSession.java:230)
~[java-driver-core-4.17.0.jar:?] at
com.datastax.oss.driver.api.core.cql.SyncCqlSession.execute(SyncCqlSession.java:54)
~[java-driver-core-4.17.0.jar:?] at
org.janusgraph.diskstorage.cql.CQLKeyColumnValueStore.initializeTable(CQLKeyColumnValueStore.java:311)
~[janusgraph-cql-1.0.0.jar:?] at
org.janusgraph.diskstorage.cql.CQLKeyColumnValueStore.(CQLKeyColumnValueStore.java:189)
~[janusgraph-cql-1.0.0.jar:?] at
org.janusgraph.diskstorage.cql.CQLStoreManager.lambda$openDatabase$7(CQLStoreManager.java:308)
~[janusgraph-cql-1.0.0.jar:?] at
java.util.concurrent.ConcurrentHashMap.computeIfAbsent(Unknown Source)
~[?:?] at
org.janusgraph.diskstorage.cql.CQLStoreManager.openDatabase(CQLStoreManager.java:308)
~[janusgraph-cql-1.0.0.jar:?]

相关配置文件 #

janusgraph-gremlin-server.yaml #

host: 0.0.0.0
port: 8182
evaluationTimeout: 30000
channelizer: org.apache.tinkerpop.gremlin.server.channel.WebSocketChannelizer
graphManager: org.janusgraph.graphdb.management.JanusGraphManager
graphs: {
  ConfigurationManagementGraph: /etc/opt/janusgraph/janusgraph.properties
}   
scriptEngines: {
  gremlin-groovy: {
    plugins: { org.janusgraph.graphdb.tinkerpop.plugin.JanusGraphGremlinPlugin: {}, 
               org.apache.tinkerpop.gremlin.server.jsr223.GremlinServerGremlinPlugin: {}, 
               org.apache.tinkerpop.gremlin.tinkergraph.jsr223.TinkerGraphGremlinPlugin: {}, 
               org.apache.tinkerpop.gremlin.jsr223.ImportGremlinPlugin: {classImports: [java.lang.Math], methodImports: [java.lang.Math#*]},
               org.apache.tinkerpop.gremlin.jsr223.ScriptFileGremlinPlugin: {files: []}}}}
serializers:
  - { className: org.apache.tinkerpop.gremlin.util.ser.GraphBinaryMessageSerializerV1,
      config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
  - { className: org.apache.tinkerpop.gremlin.util.ser.GraphBinaryMessageSerializerV1,
      config: { serializeResultToString: true }}
  - { className: org.apache.tinkerpop.gremlin.util.ser.GraphSONMessageSerializerV3,
      config: { ioRegistries: [org.janusgraph.graphdb.tinkerpop.JanusGraphIoRegistry] }}
processors:
  - { className: org.apache.tinkerpop.gremlin.server.op.session.SessionOpProcessor, config: { sessionTimeout: 28800000 }}
  - { className: org.apache.tinkerpop.gremlin.server.op.traversal.TraversalOpProcessor, config: { cacheExpirationTime: 600000, cacheMaxSize: 1000 }}

janusgraph.properties文件 #

gremlin.graph=org.janusgraph.core.ConfiguredGraphFactory
graph.graphname=ConfigurationManagementGraph

storage.backend=cql
storage.hostname=cassandra
storage.cql.local-datacenter=DC1

cache.db-cache=true
cache.db-cache-clean-wait=20
cache.db-cache-time=191000
cache.db-cache-size=0.5

解决方案 #

这个错误的核心原因是JanusGraph 1.0.0使用的DataStax Java Driver（4.17.0）与Cassandra 5.0的压缩配置语法不兼容。Cassandra 5.0修改了表压缩的配置语法，要求必须显式指定class子选项，而JanusGraph默认生成的建表CQL语句没有适配这个新语法。

提供以下三种解决思路：

1. 降级Cassandra版本：将Cassandra集群降级到4.x版本，JanusGraph 1.0.0对Cassandra 4.x的兼容性经过验证，不会出现此类语法适配问题，这是最快捷的解决方式。

2. 指定完整压缩配置参数：在janusgraph.properties中使用storage.cql.compression-options替代旧的storage.cql.compression和storage.cql.compression-type配置，传递符合Cassandra 5.0要求的完整压缩配置，示例：

storage.cql.compression-options={"class": "LZ4Compressor"}

注意需确保JanusGraph能正确解析该配置并生成合法的CQL语句。

3. 修改JanusGraph源码适配：如果需要保留Cassandra 5.0版本，可修改JanusGraph的CQL存储模块（CQLKeyColumnValueStore.java）中初始化表的逻辑，手动调整建表语句的压缩配置部分，添加class指定，之后重新编译打包JanusGraph。

内容的提问来源于stack exchange，提问作者gph