Spark将不会加载大型MySql表:Java通信链接失败-超时 [英] Spark Will Not Load Large MySql Table: Java Communications link failure - Timing Out
本文介绍了Spark将不会加载大型MySql表:Java通信链接失败-超时的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试从mysql获取一个很大的表，以便可以使用spark/databricks进行操作.我无法将其加载到火花中-我已经尝试采用较小的子集，但是即使以最小的合理单位，它仍然无法加载.
I'm trying to get a pretty large table from mysql so I can manipulate using spark/databricks. I can't get it to load into spark - I have tried taking smaller subsets, but even at the smallest reasonable unit, it still fails to load.
我尝试在mysql中使用wait_timeout和Interactive_timeout，但似乎没有任何作用
I have tried playing with the wait_timeout and interactive_timeout in mysql, but it doesn't seem to make any difference
我还加载了一个较小的(不同的)表，并且加载得很好.
I am also loading a smaller (different) table, and that loads just fine.
df_dataset = get_jdbc('raw_data_load', predicates=predicates).select('field1','field2', 'field3','date')
df_dataset = df_dataset.repartition('date')
df_dataset.registerTempTable('raw_data')
然后我尝试使用
%sql
cache table raw_data;
它运行了一段时间，以及他的数据库，但总是在30-40分钟后超时，而我在下面得到了错误
And it goes and chugs for a while and his the database, but always times out after 30-40 minutes and I get the error below
直到它超时为止，我看到
Up until the point it times out, I see
Error in SQL statement: SparkException: Job aborted due to stage failure: Task 0 in stage 30.0 failed 4 times, most recent failure: Lost task 0.3 in stage 30.0 (TID 17075, 10.200.240.63, executor 1): com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 1,715,280 milliseconds ago. The last packet sent successfully to the server was 1,715,290 milliseconds ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121)
at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:2290)
at com.mysql.jdbc.MysqlIO.nextRow(MysqlIO.java:2046)
at com.mysql.jdbc.MysqlIO.readSingleRowSet(MysqlIO.java:3554)
at com.mysql.jdbc.MysqlIO.getResultSet(MysqlIO.java:491)
at com.mysql.jdbc.MysqlIO.readResultsForQueryOrUpdate(MysqlIO.java:3245)
at com.mysql.jdbc.MysqlIO.readAllResults(MysqlIO.java:2413)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2836)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2825)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2156)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2323)
at org.apache.spark.sql.execution.datasources.jdbc.JDBCRDD.compute(JDBCRDD.scala:301)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD$$anonfun$8.apply(RDD.scala:336)
at org.apache.spark.rdd.RDD$$anonfun$8.apply(RDD.scala:334)
at org.apache.spark.storage.BlockManager$$anonfun$doPutIterator$1.apply(BlockManager.scala:1005)
at org.apache.spark.storage.BlockManager$$anonfun$doPutIterator$1.apply(BlockManager.scala:996)
at org.apache.spark.storage.BlockManager.doPut(BlockManager.scala:936)
at org.apache.spark.storage.BlockManager.doPutIterator(BlockManager.scala:996)
at org.apache.spark.storage.BlockManager.getOrElseUpdate(BlockManager.scala:700)
at org.apache.spark.rdd.RDD.getOrCompute(RDD.scala:334)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:285)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:96)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:53)
at org.apache.spark.scheduler.Task.run(Task.scala:99)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:322)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.EOFException: Can not read response from server. Expected to read 10 bytes, read 4 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3166)
at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:2271)
... 42 more
Driver stacktrace:
com.databricks.backend.common.rpc.DatabricksExceptions$SQLExecutionException: org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 30.0 failed 4 times, most recent failure: Lost task 0.3 in stage 30.0 (TID 17075, 10.200.240.63, executor 1): com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 1,715,280 milliseconds ago. The last packet sent successfully to the server was 1,715,290 milliseconds ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121)
at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:2290)
at com.mysql.jdbc.MysqlIO.nextRow(MysqlIO.java:2046)
at com.mysql.jdbc.MysqlIO.readSingleRowSet(MysqlIO.java:3554)
at com.mysql.jdbc.MysqlIO.getResultSet(MysqlIO.java:491)
at com.mysql.jdbc.MysqlIO.readResultsForQueryOrUpdate(MysqlIO.java:3245)
at com.mysql.jdbc.MysqlIO.readAllResults(MysqlIO.java:2413)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2836)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2825)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2156)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2323)
at org.apache.spark.sql.execution.datasources.jdbc.JDBCRDD.compute(JDBCRDD.scala:301)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD$$anonfun$8.apply(RDD.scala:336)
at org.apache.spark.rdd.RDD$$anonfun$8.apply(RDD.scala:334)
at org.apache.spark.storage.BlockManager$$anonfun$doPutIterator$1.apply(BlockManager.scala:1005)
at org.apache.spark.storage.BlockManager$$anonfun$doPutIterator$1.apply(BlockManager.scala:996)
at org.apache.spark.storage.BlockManager.doPut(BlockManager.scala:936)
at org.apache.spark.storage.BlockManager.doPutIterator(BlockManager.scala:996)
at org.apache.spark.storage.BlockManager.getOrElseUpdate(BlockManager.scala:700)
at org.apache.spark.rdd.RDD.getOrCompute(RDD.scala:334)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:285)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:96)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:53)
at org.apache.spark.scheduler.Task.run(Task.scala:99)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:322)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.EOFException: Can not read response from server. Expected to read 10 bytes, read 4 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3166)
at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:2271)
... 42 more
Driver stacktrace:
at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$failJobAndIndependentStages(DAGScheduler.scala:1442)
at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1430)
at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1429)
at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48)
at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:1429)
at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:803)
at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:803)
at scala.Option.foreach(Option.scala:257)
at org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:803)
at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.doOnReceive(DAGScheduler.scala:1657)
at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:1612)
at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:1601)
at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:48)
at org.apache.spark.scheduler.DAGScheduler.runJob(DAGScheduler.scala:628)
at org.apache.spark.SparkContext.runJob(SparkContext.scala:1937)
at org.apache.spark.SparkContext.runJob(SparkContext.scala:1950)
at org.apache.spark.SparkContext.runJob(SparkContext.scala:1963)
at org.apache.spark.SparkContext.runJob(SparkContext.scala:1977)
at org.apache.spark.rdd.RDD$$anonfun$collect$1.apply(RDD.scala:936)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:151)
at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:112)
at org.apache.spark.rdd.RDD.withScope(RDD.scala:362)
at org.apache.spark.rdd.RDD.collect(RDD.scala:935)
at org.apache.spark.sql.execution.SparkPlan.executeCollect(SparkPlan.scala:275)
at org.apache.spark.sql.Dataset$$anonfun$count$1.apply(Dataset.scala:2409)
at org.apache.spark.sql.Dataset$$anonfun$count$1.apply(Dataset.scala:2408)
at org.apache.spark.sql.Dataset$$anonfun$60.apply(Dataset.scala:2791)
at org.apache.spark.sql.execution.SQLExecution$$anonfun$withNewExecutionId$1.apply(SQLExecution.scala:87)
at org.apache.spark.sql.execution.SQLExecution$.withFileAccessAudit(SQLExecution.scala:53)
at org.apache.spark.sql.execution.SQLExecution$.withNewExecutionId(SQLExecution.scala:70)
at org.apache.spark.sql.Dataset.withAction(Dataset.scala:2790)
at org.apache.spark.sql.Dataset.count(Dataset.scala:2408)
at org.apache.spark.sql.execution.command.CacheTableCommand.run(cache.scala:45)
at com.databricks.sql.acl.TrustedRunnableCommand$$anonfun$run$1.apply(TrustedRunnableCommand.scala:29)
at com.databricks.sql.acl.TrustedRunnableCommand$$anonfun$run$1.apply(TrustedRunnableCommand.scala:29)
at com.databricks.sql.acl.CheckPermissions$.trusted(CheckPermissions.scala:460)
at com.databricks.sql.acl.TrustedRunnableCommand.run(TrustedRunnableCommand.scala:29)
at org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult$lzycompute(commands.scala:58)
at org.apache.spark.sql.execution.command.ExecutedCommandExec.sideEffectResult(commands.scala:56)
at org.apache.spark.sql.execution.command.ExecutedCommandExec.executeCollect(commands.scala:67)
at org.apache.spark.sql.Dataset.<init>(Dataset.scala:185)
at org.apache.spark.sql.Dataset$.ofRows(Dataset.scala:64)
at org.apache.spark.sql.SparkSession.sql(SparkSession.scala:599)
at org.apache.spark.sql.SQLContext.sql(SQLContext.scala:698)
at com.databricks.backend.daemon.driver.SQLDriverLocal$$anonfun$1.apply(SQLDriverLocal.scala:82)
at com.databricks.backend.daemon.driver.SQLDriverLocal$$anonfun$1.apply(SQLDriverLocal.scala:28)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
at scala.collection.immutable.List.foreach(List.scala:381)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:234)
at scala.collection.immutable.List.map(List.scala:285)
at com.databricks.backend.daemon.driver.SQLDriverLocal.executeSql(SQLDriverLocal.scala:28)
at com.databricks.backend.daemon.driver.SQLDriverLocal.repl(SQLDriverLocal.scala:128)
at com.databricks.backend.daemon.driver.DriverLocal$$anonfun$execute$2.apply(DriverLocal.scala:230)
at com.databricks.backend.daemon.driver.DriverLocal$$anonfun$execute$2.apply(DriverLocal.scala:211)
at com.databricks.logging.UsageLogging$$anonfun$withAttributionContext$1.apply(UsageLogging.scala:173)
at scala.util.DynamicVariable.withValue(DynamicVariable.scala:58)
at com.databricks.logging.UsageLogging$class.withAttributionContext(UsageLogging.scala:168)
at com.databricks.backend.daemon.driver.DriverLocal.withAttributionContext(DriverLocal.scala:39)
at com.databricks.logging.UsageLogging$class.withAttributionTags(UsageLogging.scala:206)
at com.databricks.backend.daemon.driver.DriverLocal.withAttributionTags(DriverLocal.scala:39)
at com.databricks.backend.daemon.driver.DriverLocal.execute(DriverLocal.scala:211)
at com.databricks.backend.daemon.driver.DriverWrapper$$anonfun$tryExecutingCommand$2.apply(DriverWrapper.scala:589)
at com.databricks.backend.daemon.driver.DriverWrapper$$anonfun$tryExecutingCommand$2.apply(DriverWrapper.scala:589)
at scala.util.Try$.apply(Try.scala:192)
at com.databricks.backend.daemon.driver.DriverWrapper.tryExecutingCommand(DriverWrapper.scala:584)
at com.databricks.backend.daemon.driver.DriverWrapper.executeCommand(DriverWrapper.scala:488)
at com.databricks.backend.daemon.driver.DriverWrapper.runInnerLoop(DriverWrapper.scala:391)
at com.databricks.backend.daemon.driver.DriverWrapper.runInner(DriverWrapper.scala:348)
at com.databricks.backend.daemon.driver.DriverWrapper.run(DriverWrapper.scala:215)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 1,715,280 milliseconds ago. The last packet sent successfully to the server was 1,715,290 milliseconds ago.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121)
at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:2290)
at com.mysql.jdbc.MysqlIO.nextRow(MysqlIO.java:2046)
at com.mysql.jdbc.MysqlIO.readSingleRowSet(MysqlIO.java:3554)
at com.mysql.jdbc.MysqlIO.getResultSet(MysqlIO.java:491)
at com.mysql.jdbc.MysqlIO.readResultsForQueryOrUpdate(MysqlIO.java:3245)
at com.mysql.jdbc.MysqlIO.readAllResults(MysqlIO.java:2413)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2836)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2825)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2156)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2323)
at org.apache.spark.sql.execution.datasources.jdbc.JDBCRDD.compute(JDBCRDD.scala:301)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD$$anonfun$8.apply(RDD.scala:336)
at org.apache.spark.rdd.RDD$$anonfun$8.apply(RDD.scala:334)
at org.apache.spark.storage.BlockManager$$anonfun$doPutIterator$1.apply(BlockManager.scala:1005)
at org.apache.spark.storage.BlockManager$$anonfun$doPutIterator$1.apply(BlockManager.scala:996)
at org.apache.spark.storage.BlockManager.doPut(BlockManager.scala:936)
at org.apache.spark.storage.BlockManager.doPutIterator(BlockManager.scala:996)
at org.apache.spark.storage.BlockManager.getOrElseUpdate(BlockManager.scala:700)
at org.apache.spark.rdd.RDD.getOrCompute(RDD.scala:334)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:285)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:96)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:53)
at org.apache.spark.scheduler.Task.run(Task.scala:99)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:322)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
... 1 more
Caused by: java.io.EOFException: Can not read response from server. Expected to read 10 bytes, read 4 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3166)
at com.mysql.jdbc.MysqlIO.nextRowFast(MysqlIO.java:2271)
... 42 more
at com.databricks.backend.daemon.driver.SQLDriverLocal.executeSql(SQLDriverLocal.scala:116)
at com.databricks.backend.daemon.driver.SQLDriverLocal.repl(SQLDriverLocal.scala:128)
at com.databricks.backend.daemon.driver.DriverLocal$$anonfun$execute$2.apply(DriverLocal.scala:230)
at com.databricks.backend.daemon.driver.DriverLocal$$anonfun$execute$2.apply(DriverLocal.scala:211)
at com.databricks.logging.UsageLogging$$anonfun$withAttributionContext$1.apply(UsageLogging.scala:173)
at scala.util.DynamicVariable.withValue(DynamicVariable.scala:58)
at com.databricks.logging.UsageLogging$class.withAttributionContext(UsageLogging.scala:168)
at com.databricks.backend.daemon.driver.DriverLocal.withAttributionContext(DriverLocal.scala:39)
at com.databricks.logging.UsageLogging$class.withAttributionTags(UsageLogging.scala:206)
at com.databricks.backend.daemon.driver.DriverLocal.withAttributionTags(DriverLocal.scala:39)
at com.databricks.backend.daemon.driver.DriverLocal.execute(DriverLocal.scala:211)
at com.databricks.backend.daemon.driver.DriverWrapper$$anonfun$tryExecutingCommand$2.apply(DriverWrapper.scala:589)
at com.databricks.backend.daemon.driver.DriverWrapper$$anonfun$tryExecutingCommand$2.apply(DriverWrapper.scala:589)
at scala.util.Try$.apply(Try.scala:192)
at com.databricks.backend.daemon.driver.DriverWrapper.tryExecutingCommand(DriverWrapper.scala:584)
at com.databricks.backend.daemon.driver.DriverWrapper.executeCommand(DriverWrapper.scala:488)
at com.databricks.backend.daemon.driver.DriverWrapper.runInnerLoop(DriverWrapper.scala:391)
at com.databricks.backend.daemon.driver.DriverWrapper.runInner(DriverWrapper.scala:348)
at com.databricks.backend.daemon.driver.DriverWrapper.run(DriverWrapper.scala:215)
at java.lang.Thread.run(Thread.java:745)
推荐答案
对于非常大的表，您将需要在执行程序之间对查询进行分区.默认情况下，JDBC阅读器将从驱动程序中读取查询以使其并行化.如果表中有递增的顺序键，则可以使用lowerBound，upperBound和numPartitions参数进行并行化.这是一个来自 https://docs的示例.databricks.com/spark/latest/data-sources/sql-databases.html#python-example
With extremely large tables you're going to want to partition the query across your executors. By default the JDBC reader will read the query the parallelize it from the driver. If you have an incrementing, sequential key in the table you can parallelize using the lowerBound, upperBound, and numPartitions parameters. Here's an example taken from https://docs.databricks.com/spark/latest/data-sources/sql-databases.html#python-example
df = spark.read.\
jdbc(url=jdbcUrl, \
table='employees',\
column='emp_no',\
lowerBound=1,\
upperBound=100000, \
numPartitions=100)
df.show()
话虽如此，您可能希望将数据读写到Parquet中，因为这样做比重新从JDBC重新读取要好.
Having said that, you may want to read and write the data out to Parquet as that will perform better than re-reading from JDBC again.
这篇关于Spark将不会加载大型MySql表:Java通信链接失败-超时的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
