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https://issues.apache.org/jira/browse/KUDU-3205?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Grant Henke reassigned KUDU-3205:
---------------------------------
Assignee: Grant Henke
> NPE in KuduScanTokenBuilder#build after a tablet server goes down
> -----------------------------------------------------------------
>
> Key: KUDU-3205
> URL: https://issues.apache.org/jira/browse/KUDU-3205
> Project: Kudu
> Issue Type: Bug
> Components: spark
> Affects Versions: 1.13.0
> Reporter: Junegunn Choi
> Assignee: Grant Henke
> Priority: Major
>
> When a tablet server goes down while running a query on Spark, the connection
> becomes unusable due to the cached tablet locations that have become stale.
> h2. Steps to reproduce
> h3. Start spark-shell with kudu-spark2 1.13.0
> The problem is not reproducible with kudu-spark2 1.12.0 or below, because it
> was introduced in [KUDU-1802
> |https://github.com/apache/kudu/commit/d23ee5d38ddc4317f431dd65df0c825c00cc968a].
> h3. Run a scan query
> {code:scala}
> import org.apache.kudu.spark.kudu._
> val dummy = spark.read.options(Map("kudu.master" -> kuduMasters, "kudu.table"
> -> "dummy")).kudu
> dummy.createOrReplaceTempView("dummy")
> spark.sql("select sum(id), min(val2), max(val2), count(*) from dummy").show
> {code}
> h3. Kill a tablet server
> Kill one of the tablet servers that are serving data for the query. The query
> should fail immediately.
> {noformat}
> org.apache.spark.SparkException: Job aborted due to stage failure: Task 2 in
> stage 0.0 failed 1 times, most recent failure: Lost task 2.0 in stage 0.0
> (TID 2, localhost, executor driver): java.lang.RuntimeException:
> org.apache.kudu.client.NonRecoverableException: Scanner *** not found (it may
> have expired)
> {noformat}
> h3. Re-run the query
> {code:scala}
> spark.sql("select sum(id), min(val2), max(val2), count(*) from dummy").show
> {code}
> Doesn't work, fails with an NPE.
> {noformat}
> Caused by: java.lang.RuntimeException: java.lang.NullPointerException
> at
> org.apache.kudu.client.KuduScanToken$KuduScanTokenBuilder.build(KuduScanToken.java:697)
> at org.apache.kudu.spark.kudu.KuduRDD.getPartitions(KuduRDD.scala:95)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:273)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:269)
> at scala.Option.getOrElse(Option.scala:121)
> at org.apache.spark.rdd.RDD.partitions(RDD.scala:269)
> at
> org.apache.spark.rdd.MapPartitionsRDD.getPartitions(MapPartitionsRDD.scala:49)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:273)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:269)
> at scala.Option.getOrElse(Option.scala:121)
> at org.apache.spark.rdd.RDD.partitions(RDD.scala:269)
> at
> org.apache.spark.rdd.MapPartitionsRDD.getPartitions(MapPartitionsRDD.scala:49)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:273)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:269)
> at scala.Option.getOrElse(Option.scala:121)
> at org.apache.spark.rdd.RDD.partitions(RDD.scala:269)
> at
> org.apache.spark.rdd.MapPartitionsRDD.getPartitions(MapPartitionsRDD.scala:49)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:273)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:269)
> at scala.Option.getOrElse(Option.scala:121)
> at org.apache.spark.rdd.RDD.partitions(RDD.scala:269)
> at
> org.apache.spark.rdd.MapPartitionsRDD.getPartitions(MapPartitionsRDD.scala:49)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:273)
> at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:269)
> at scala.Option.getOrElse(Option.scala:121)
> at org.apache.spark.rdd.RDD.partitions(RDD.scala:269)
> at org.apache.spark.ShuffleDependency.<init>(Dependency.scala:94)
> at
> org.apache.spark.sql.execution.exchange.ShuffleExchangeExec$.prepareShuffleDependency(ShuffleExchangeExec.scala:323)
> at
> org.apache.spark.sql.execution.exchange.ShuffleExchangeExec.prepareShuffleDependency(ShuffleExchangeExec.scala:91)
> at
> org.apache.spark.sql.execution.exchange.ShuffleExchangeExec$$anonfun$doExecute$1.apply(ShuffleExchangeExec.scala:128)
> at
> org.apache.spark.sql.execution.exchange.ShuffleExchangeExec$$anonfun$doExecute$1.apply(ShuffleExchangeExec.scala:119)
> at
> org.apache.spark.sql.catalyst.errors.package$.attachTree(package.scala:52)
> ... 86 more
> Caused by: java.lang.NullPointerException
> at
> org.apache.kudu.client.KuduScanToken$KuduScanTokenBuilder.build(KuduScanToken.java:674)
> ... 117 more
> {noformat}
> Re-creating the DataFrame doesn't help:
> {code:scala}
> val dummy = spark.read.options(Map("kudu.master" -> kuduMasters, "kudu.table"
> -> "dummy")).kudu
> dummy.createOrReplaceTempView("dummy")
> // Still fails with an NPE
> spark.sql("select sum(id), min(val2), max(val2), count(*) from dummy").show
> {code}
> h2. Cause
> {code:java|title=KuduScanToken.java:666}
> // Build the list of replica metadata.
> List<Client.TabletMetadataPB.ReplicaMetadataPB> replicas = new ArrayList<>();
> for (LocatedTablet.Replica replica : remoteTablet.getReplicas()) {
> Integer serverIndex = serverIndexMap.get(
> new HostAndPort(replica.getRpcHost(), replica.getRpcPort()));
> Client.TabletMetadataPB.ReplicaMetadataPB.Builder tabletMetadataBuilder =
> Client.TabletMetadataPB.ReplicaMetadataPB.newBuilder()
> .setRole(replica.getRoleAsEnum())
> .setTsIdx(serverIndex);
> if (replica.getDimensionLabel() != null) {
> tabletMetadataBuilder.setDimensionLabel(replica.getDimensionLabel());
> }
> replicas.add(tabletMetadataBuilder.build());
> }
> {code}
> {{serverIndex}} can be null here, because we're using the cached tablet
> locations that are stale now ({{TableLocationsCache.Entry}}).
> h2. Workarounds
> - Restart Spark shell
> - Wait until the connection becomes idle and cleaned up
> {noformat}
> DEBUG Connection: [peer master-***] handling channelInactive
> DEBUG Connection: [peer master-***] cleaning up while in state READY due to:
> connection closed
> {noformat}
> - Use kudu-spark2 1.12.0 or below
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