[jira] [Comment Edited] (TOREE-349) ClassCastException when reading Avro from another thread (Toree master / Spark 2.0.0)
[
https://issues.apache.org/jira/browse/TOREE-349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15582769#comment-15582769
]
Andrew Kerr edited comment on TOREE-349 at 10/17/16 5:06 PM:
-
This code works as expected:
{code:language=scala}
val classLoader = Thread.currentThread().getContextClassLoader
println(classLoader)
val future = Future{
Thread.currentThread().setContextClassLoader(classLoader)
session.read.avro("foo")
}
val result = Await.result(future, Duration.Inf)
result.show()
{code}
The classloader is
scala.tools.nsc.interpreter.IMain$TranslatingClassLoader@864ff30
Obviously this isn't ideal. It also isn't necessary for loading CSV files,
which are implemented in a similar way to the Avro loader (as in the Avro code
looks copy-pasted from CSV).
was (Author: andrewkerr):
This code works as expected:
{code}
val classLoader = Thread.currentThread().getContextClassLoader
println(classLoader)
val future = Future{
Thread.currentThread().setContextClassLoader(classLoader)
session.read.avro("foo")
}
val result = Await.result(future, Duration.Inf)
result.show()
{code}
The classloader is
scala.tools.nsc.interpreter.IMain$TranslatingClassLoader@864ff30
Obviously this isn't ideal. It also isn't necessary for loading CSV files,
which are implemented in a similar way to the Avro loader (as in the Avro code
looks copy-pasted from CSV).
> ClassCastException when reading Avro from another thread (Toree master /
> Spark 2.0.0)
> -
>
> Key: TOREE-349
> URL: https://issues.apache.org/jira/browse/TOREE-349
> Project: TOREE
> Issue Type: Bug
>Reporter: Andrew Kerr
> Attachments: avro-csv-threading.scala.ipynb, run.sh
>
>
> When using Toree (master branch commit
> e8ecd0623c65ad104045b1797fb27f69b8dfc23f)
> with `--packages=com.databricks:spark-avro_2.11:3.0.1` in `SPARK_OPTS`
> and attempting to load an avro file into a dataframe *in a separate thread*
> then an exception is thrown
> `java.lang.ClassCastException:
> com.databricks.spark.avro.DefaultSource$SerializableConfiguration cannot be
> cast to com.databricks.spark.avro.DefaultSource$SerializableConfiguration`
> here
> https://github.com/databricks/spark-avro/blob/v3.0.1/src/main/scala/com/databricks/spark/avro/DefaultSource.scala#L156
> Will attach a Jupyter notebook that illustrates the problem and includes full
> stack trace, with a script showing environment.
> The class that throws the exception `DefaultSource` broadcasts Hadoop config
> and returns an anonymous function that accesses that config. The exception
> occurs when that function is executed and it attempts to access the config.
> This looks like a class loader mismatch problem to me ("Class Identity
> Crisis").
> With a bit of hacking of `spark-avro` I've seen the class loader for
> `DefaultSource` when the config is broadcast to be
> `scala.reflect.internal.util.ScalaClassLoader$URLClassLoader@31ac5411`
> and when the config is read to be
> `org.apache.spark.util.MutableURLClassLoader@3d3fcdb0`
> If a fat jar including `spark-avro` is built and included with `--jars=...`
> then the same problem occurs.
> Interestingly the Spark's included support for CSV uses the same pattern as
> Avro, broadcasting a config, but works as expected as shown in the notebook.
> https://github.com/apache/spark/blob/v2.0.0/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVFileFormat.scala#L108
> Avro also works as expected when an application fat jar is built and passed
> to
> `spark-submit` without involving Toree.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
[jira] [Comment Edited] (TOREE-349) ClassCastException when reading Avro from another thread (Toree master / Spark 2.0.0)
[
https://issues.apache.org/jira/browse/TOREE-349?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15582769#comment-15582769
]
Andrew Kerr edited comment on TOREE-349 at 10/17/16 5:04 PM:
-
This code works as expected:
{code}
val classLoader = Thread.currentThread().getContextClassLoader
println(classLoader)
val future = Future{
Thread.currentThread().setContextClassLoader(classLoader)
session.read.avro("foo")
}
val result = Await.result(future, Duration.Inf)
result.show()
{code}
The classloader is
scala.tools.nsc.interpreter.IMain$TranslatingClassLoader@864ff30
Obviously this isn't ideal. It also isn't necessary for loading CSV files,
which are implemented in a similar way to the Avro loader (as in the Avro code
looks copy-pasted from CSV).
was (Author: andrewkerr):
This code works as expected:
```
val classLoader = Thread.currentThread().getContextClassLoader
println(classLoader)
val future = Future{
Thread.currentThread().setContextClassLoader(classLoader)
session.read.avro("foo")
}
val result = Await.result(future, Duration.Inf)
result.show()
```
The classloader is
`scala.tools.nsc.interpreter.IMain$TranslatingClassLoader@864ff30`
Obviously this isn't ideal. It also isn't necessary for loading CSV files,
which are implemented in a similar way to the Avro loader (as in the Avro code
looks copy-pasted from CSV).
> ClassCastException when reading Avro from another thread (Toree master /
> Spark 2.0.0)
> -
>
> Key: TOREE-349
> URL: https://issues.apache.org/jira/browse/TOREE-349
> Project: TOREE
> Issue Type: Bug
>Reporter: Andrew Kerr
> Attachments: avro-csv-threading.scala.ipynb, run.sh
>
>
> When using Toree (master branch commit
> e8ecd0623c65ad104045b1797fb27f69b8dfc23f)
> with `--packages=com.databricks:spark-avro_2.11:3.0.1` in `SPARK_OPTS`
> and attempting to load an avro file into a dataframe *in a separate thread*
> then an exception is thrown
> `java.lang.ClassCastException:
> com.databricks.spark.avro.DefaultSource$SerializableConfiguration cannot be
> cast to com.databricks.spark.avro.DefaultSource$SerializableConfiguration`
> here
> https://github.com/databricks/spark-avro/blob/v3.0.1/src/main/scala/com/databricks/spark/avro/DefaultSource.scala#L156
> Will attach a Jupyter notebook that illustrates the problem and includes full
> stack trace, with a script showing environment.
> The class that throws the exception `DefaultSource` broadcasts Hadoop config
> and returns an anonymous function that accesses that config. The exception
> occurs when that function is executed and it attempts to access the config.
> This looks like a class loader mismatch problem to me ("Class Identity
> Crisis").
> With a bit of hacking of `spark-avro` I've seen the class loader for
> `DefaultSource` when the config is broadcast to be
> `scala.reflect.internal.util.ScalaClassLoader$URLClassLoader@31ac5411`
> and when the config is read to be
> `org.apache.spark.util.MutableURLClassLoader@3d3fcdb0`
> If a fat jar including `spark-avro` is built and included with `--jars=...`
> then the same problem occurs.
> Interestingly the Spark's included support for CSV uses the same pattern as
> Avro, broadcasting a config, but works as expected as shown in the notebook.
> https://github.com/apache/spark/blob/v2.0.0/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/csv/CSVFileFormat.scala#L108
> Avro also works as expected when an application fat jar is built and passed
> to
> `spark-submit` without involving Toree.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
