InvalidQueryException：此操作不支持一致性级别LOCAL_ONE支持的一致性级别为：LOCAL_QUORUM

问题描述

import org.apache.spark._
import org.apache.spark.SparkContext._
import com.datastax.spark.connector._
import com.datastax.spark.connector.cql.CassandraConnector    
val conf = new SparkConf()
          .setMaster("local[*]")
          .setAppName("XXXX")
          .set("spark.cassandra.connection.host","cassandra.us-east-2.amazonaws.com")
          .set("spark.cassandra.connection.port","9142")
          .set("spark.cassandra.auth.username","XXXXX")
          .set("spark.cassandra.auth.password","XXXXX")
          .set("spark.cassandra.connection.ssl.enabled","true")
          .set("spark.cassandra.connection.ssl.trustStore.path","/home/nihad/.cassandra/cassandra_truststore.jks")
          .set("spark.cassandra.connection.ssl.trustStore.password","XXXXX")
          .set("spark.cassandra.output.consistency.level","LOCAL_QUORUM")
    
    val connector = CassandraConnector(conf)
           val session = connector.openSession()
               sesssion.execute("""INSERT INTO "covid19".delta_by_states (state_code,state_value,date ) VALUES ('kl',5,'2020-03-03');""")
session.close()

我试图使用我本地系统中设置的Spark App将数据写入AWS Cassandra Keyspace。 问题是当我执行上述代码时，出现如下异常：

“ com.datastax.oss.driver.api.core.servererrors.InvalidQueryException： 此操作不支持一致性级别LOCAL_ONE。 支持的一致性级别为：LOCAL_QUORUM“

从上面的代码中可以看到，我已经在spark conf中将cassandra.output.consistency.level设置为LOCAL_QUORUM。我也在使用datastax cassandra驱动程序。

但是当我从AWS Cassandra读取数据时，它可以正常工作。我也在AWS Keyspace cqlsh中尝试了相同的INSERT命令。那里也很好。因此查询有效。

有人可以帮助我如何通过datastax.CassandraConnector设置一致性吗？

解决方法

破解。

不是通过spark配置来设置cassandra一致性。我在src / main / resources目录中创建了一个application.conf文件。

    datastax-java-driver {

        basic.contact-points = [ "cassandra.us-east-2.amazonaws.com:9142"]
    advanced.auth-provider{
        class = PlainTextAuthProvider
        username = "serviceUserName"
        password = "servicePassword"
    }
    basic.load-balancing-policy {
        local-datacenter = "us-east-2"
    }

    advanced.ssl-engine-factory {
        class = DefaultSslEngineFactory
        truststore-path = "yourPath/.cassandra/cassandra_truststore.jks"
        truststore-password = "trustorePassword"
      }

    basic.request.consistency = LOCAL_QUORUM 
    basic.request.timeout = 5 seconds 
    
}

并创建了如下所示的cassandra会话

import com.datastax.oss.driver.api.core.config.DriverConfigLoader
import com.datastax.oss.driver.api.core.CqlSession

val loader = DriverConfigLoader.fromClassPath("application.conf")
val session = CqlSession.builder().withConfigLoader(loader).build()
sesssion.execute("""INSERT INTO "covid19".delta_by_states (state_code,state_value,date ) VALUES ('kl',5,'2020-03-03');""")

终于成功了。无需弄乱spark配置 驱动程序配置https://docs.datastax.com/en/drivers/java/4.0/com/datastax/oss/driver/api/core/config/DriverConfigLoader.html#fromClasspath-java.lang.String-

的文档

datastax配置文档https://docs.datastax.com/en/developer/java-driver/4.6/manual/core/configuration/reference/