Spark 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
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问题描述
我正在尝试从 mysql 获取一个相当大的表，以便我可以使用 spark/databricks 进行操作.我无法将其加载到 spark 中 - 我尝试采用较小的子集，但即使在最小的合理单位下，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，但它似乎没有任何区别
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(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;
它和他的数据库持续了一段时间，但总是在 30-40 分钟后超时，我收到以下错误
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
直到超时，我看到
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，您将希望跨执行程序对查询进行分区.默认情况下，JDBC 读取器将从驱动程序读取查询并将其并行化.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.这是从 https://docs 中获取的示例.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取和写入 Parquet，因为这比再次从 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.
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