分区键部分url的无效空值

Question

 val imageKeywords = sc.cassandraTable[ImageMetadata]("images", "metadata")
 val imageAndPageKeywords = imageKeywords
  .joinWithCassandraTable[PagesMetadata]("pages2", "metadata")
  .on(SomeColumns("tid", "url" as "pu"))

case class ImageMetadata(tid: String, iu: String, pu: Option[String],
mk: List[String], fk: List[String], ak: List[String], ipk: List[String], pk: List[String], ik: List[String], ck: List[String])

case class PagesMetadata(tid: String, url: String, pk: List[String], uk: List[String], hk: List[String], ok: List[String], tc: List[String])

当我尝试执行以下操作时，我得到了一个错误

imageAndPageKeywords.collect.toList.sortBy(_._1.tid).take(10).foreach(println)

错误stacktrace-

由：com.datastax.driver.core.exceptions.invalidQueryException：在com.datastax.driver.core.responction$error.asexception(response.java:103)在com.datastax.driver.core.defaultsultsetfuture.onset（defaultsultsetfuture.java:140)在com.datastax.driver.core.requesthandler.java:293)在在org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpper(simpleChannelUpstreamHandler.java:70)在org.jboss.netty.handler.timeout.idleStateAwareChannelUpstreamHandler.handleUpper(idleStateAwareChannelUpstreamHandler.java:36)在org.jboss.netty.channel.defaultChannelPipeline.sendupStreamStream.java:564)在channelPipeline.java:791)位于org.jboss.netty.handler.timeout.idleStateHandler.messageReceed(idleStateHandler.java:294)在org.jboss.netty.channel.simpleChanneLupStreamHandler.handleUpper(simpleChanneLupStreamHandler.java:70)在org.jboss.netty.channel.defaultChannelHandler.java:70)在org.jboss.netty.channel.defaultChannelPipeline.sendupStream（Eceed(channels.java:296)在org.jboss.netty.handler.codec.oneTooneDecoder.handleUpstream（oneTooneDecoder.java:70)在org.jboss.netty.channel.defaultChannelPipeline.sendupstream（defaultChannelPipeline.java:564)在org.jboss.netty.channel.defaultChannelPipeline.java:564)在.frame.frameDecoder.unfoldandFireMessageReceed(frameDecoder.java:462)位于org.jboss.netty.handler.codec.frame.frameDecoder.calldecode(frameDecoder.java:443)在org.jboss.netty.channel.simpleChannelupStreamHandler.handleUpper(simpleChannelupStreamHandler.java:303)在org.jboss.netty.channel.defaultChannelPipeline.java:70)在org.jboss.netty.channel.defaultChannelPipeline.java:564)在firemessageReceed（channels.java:268)在org.jboss.netty.channel.channels.firemessageReceed（channels.java:255)在org.jboss.netty.channel.nio.nioworker.read（nioworker.java:88)在org.jboss.netty.nocket.nio.abstractnioworker.process(abstractnioworker.process（abstractnioworker.java:108)在el.socket.nio.abstractnioworker.run（abstractnioworker.java:89)位于org.jboss.netty.channel.socket.nio.niowor在org.jboss.netty.util.threadrenamingrunnable.run(threadrenamingrunnable.java:108)在org.jboss.netty.util.internal.deadlockproofworker$1.run(deadlockproofworker.java:42)...3个更多

Answer 1

简单地说，该异常告诉您它无法执行联接，因为用于联接ImageMetadata和PagesMetadata的列为NULL。

在您的示例中，ImageMetadata中的某些url(pu)值为空。

奇怪的是，您使用url nullable(option[String])定义PagesMetadata，它似乎是表主键的一部分

val imageAndPageKeywords = imageKeywords
  .filter(im -> im.pu.isDefined)
  .joinWithCassandraTable[PagesMetadata]("pages2", "metadata")
  .on(SomeColumns("tid", "url" as "pu"))