Cassandra slice query not working with composite key
I am new to scala and I want to convert my Java code to scala. my database is a cassandra family and column family definition similar to this
Family name :colFam
Rowkey: rowKey1
=>(name=comkey1:comkey1,value='xyz',timestamp=1554515485)
=>(name=comkey1:comkey2,value='xyz',timestamp=1554515485)
=>(name=comkey1:comkey3,value='xyz',timestamp=1554515485)
=>(name=comkey1:comkey4,value='xyz',timestamp=1554515485)
=>(name=comkey1:comkey5,value='xyz',timestamp=1554515485)
-------------------------------------------------------
Rowkey: rowKey2
=>(name=comkey1:comkey3,value='abc',timestamp=1554515485)
-------------------------------------------------------
Rowkey: rowKey4
=>(name=comkey1:comkey4,value='pqr',timestamp=1554515485)
-------------------------------------------------------
now i want to get all record from cassandra and my columnQuery function is working fine
val sliceQuery = HFactory.createColumnQuery(rankqKeyspace, StringSerializer.get(), new CompositeSerializer(), StringSerializer.get())
the problem is in my sliceQuery, usually the slice query works fine with simple column name, but when I used the type column type it was giving me the error
var startKey = new Composite();
var endKey = new Composite();
startKey.addComponent("comkey1", se);
startKey.addComponent("comkey2", se);
endKey.addComponent("comkey1", se);
endKey.addComponent("comkey4", se);
val sliceQuery = HFactory.createSliceQuery(rankqKeyspace, se, new CompositeSerializer(), se)
slicesQuery.setColumnFamily("colFam");
slicesQuery.setKey(rowKey1)
slicesQuery.setRange(startKey, endKey, false, Integer.MAX_VALUE);
val result = slicesQuery.execute()
val orderedRows = result.get();
it gives me a "NullPointerException" error
val orderedRows = result.get();
println(orderedRows)
this string always returns null
Change question
Stack trace
java.lang.NullPointerException
at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:191)
at com.google.common.collect.ImmutableClassToInstanceMap.getInstance(ImmutableClassToInstanceMap.java:147)
at me.prettyprint.hector.api.beans.AbstractComposite.serializerForComparator(AbstractComposite.java:321)
at me.prettyprint.hector.api.beans.AbstractComposite.getSerializer(AbstractComposite.java:344)
at me.prettyprint.hector.api.beans.AbstractComposite.deserialize(AbstractComposite.java:708)
at me.prettyprint.cassandra.serializers.CompositeSerializer.fromByteBuffer(CompositeSerializer.java:29)
at me.prettyprint.cassandra.serializers.CompositeSerializer.fromByteBuffer(CompositeSerializer.java:17)
at me.prettyprint.cassandra.model.HColumnImpl.getName(HColumnImpl.java:111)
at me.prettyprint.cassandra.model.HColumnImpl.toString(HColumnImpl.java:202)
at java.lang.String.valueOf(String.java:2854)
at java.lang.StringBuilder.append(StringBuilder.java:128)
at java.util.AbstractCollection.toString(AbstractCollection.java:450)
at me.prettyprint.cassandra.model.ColumnSliceImpl.toString(ColumnSliceImpl.java:54)
at java.lang.String.valueOf(String.java:2854)
at java.io.PrintStream.println(PrintStream.java:821)
at scala.Console$.println(Console.scala:240)
at scala.Predef$.println(Predef.scala:287)
at models.PinModel$.testColCompositeKey(PinModel.scala:178)
at controllers.PinController$$anonfun$test$1.apply(PinController.scala:52)
at controllers.PinController$$anonfun$test$1.apply(PinController.scala:49)
at play.api.mvc.ActionBuilder$$anonfun$apply$10.apply(Action.scala:221)
at play.api.mvc.ActionBuilder$$anonfun$apply$10.apply(Action.scala:220)
at play.api.mvc.Action$.invokeBlock(Action.scala:357)
at play.api.mvc.ActionBuilder$$anon$1.apply(Action.scala:309)
at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4$$anonfun$apply$5.apply(Action.scala:109)
at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4$$anonfun$apply$5.apply(Action.scala:109)
at play.utils.Threads$.withContextClassLoader(Threads.scala:18)
at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4.apply(Action.scala:108)
at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4.apply(Action.scala:107)
at scala.Option.map(Option.scala:145)
at play.api.mvc.Action$$anonfun$apply$1.apply(Action.scala:107)
at play.api.mvc.Action$$anonfun$apply$1.apply(Action.scala:100)
at play.api.libs.iteratee.Iteratee$$anonfun$mapM$1.apply(Iteratee.scala:481)
at play.api.libs.iteratee.Iteratee$$anonfun$mapM$1.apply(Iteratee.scala:481)
at play.api.libs.iteratee.Iteratee$$anonfun$flatMapM$1.apply(Iteratee.scala:517)
at play.api.libs.iteratee.Iteratee$$anonfun$flatMapM$1.apply(Iteratee.scala:517)
at play.api.libs.iteratee.Iteratee$$anonfun$flatMap$1$$anonfun$apply$13.apply(Iteratee.scala:493)
at play.api.libs.iteratee.Iteratee$$anonfun$flatMap$1$$anonfun$apply$13.apply(Iteratee.scala:493)
at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1$1(Future.scala:24)
at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24)
at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:42)
at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386)
at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
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2 answers
Anyone facing the same problem here, Hector does not work very well with the latest version of Google Guava which leads to this error, check if there are any libraries depending on the other version of Guava. For my exact situation, I ended up using Guava 13.0 as it also contained parts that were needed for another library.
I would recommend moving away from Hector if at all possible, it is no longer supported. I personally started migrating to the new Datastax driver using CQL and it makes a lot of things easier.
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I think you need to explicitly set up the serializer by position for each of your composite keys:
var startKey = new Composite();
startKey.setSerializerByPosition(0, comkey1Serializer)
startKey.setSerializerByPosition(1, comkey2Serializer)
startKey.addComponent("comkey1", se);
startKey.addComponent("comkey2", se);
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