我正在Azure Databricks平台，DSE 6.0.7和Spark cassandra连接器版本2.4.0中使用spark 2.4和scala 2.11
在获得一张约有1亿条记录的表的计数时，我遇到了错误。其中一个应用程序需要确切的行数。以下是我的代码-
val count = spark.read
.format("org.apache.spark.sql.cassandra")
.option("table", tableName)
.option("keyspace", keyspace)
.load()
.count()
以下是例外-
java.io.IOException: Exception during execution of SELECT count(*) FROM "mykeyspace"."mytable" WHERE token("id") > ? AND token("id") <= ? ALLOW FILTERING: [/host:9042] Timed out waiting for server response
at com.datastax.spark.connector.rdd.CassandraTableScanRDD.com$datastax$spark$connector$rdd$CassandraTableScanRDD$$fetchTokenRange(CassandraTableScanRDD.scala:350)
at com.datastax.spark.connector.rdd.CassandraTableScanRDD$$anonfun$17.apply(CassandraTableScanRDD.scala:367)
at com.datastax.spark.connector.rdd.CassandraTableScanRDD$$anonfun$17.apply(CassandraTableScanRDD.scala:367)
at scala.collection.Iterator$$anon$12.nextCur(Iterator.scala:434)
at scala.collection.Iterator$$anon$12.hasNext(Iterator.scala:440)
at com.datastax.spark.connector.util.CountingIterator.hasNext(CountingIterator.scala:12)
at scala.collection.Iterator$$anon$12.hasNext(Iterator.scala:439)
at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:408)
at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage1.agg_doAggregateWithoutKey_0$(Unknown Source)
at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage1.processNext(Unknown Source)
at org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
at org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$13$$anon$1.hasNext(WholeStageCodegenExec.scala:634)
at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:408)
at org.apache.spark.shuffle.sort.BypassMergeSortShuffleWriter.write(BypassMergeSortShuffleWriter.java:125)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:99)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:55)
at org.apache.spark.scheduler.Task.doRunTask(Task.scala:139)
at org.apache.spark.scheduler.Task.run(Task.scala:112)
at org.apache.spark.executor.Executor$TaskRunner$$anonfun$13.apply(Executor.scala:497)
at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1432)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:503)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: com.datastax.driver.core.exceptions.OperationTimedOutException: [/host:9042] Timed out waiting for server response