Hi all, We are encountering $subject in ML, for the default hyper-parameter values. A similar issue has been reported in [1], but with a different algorithm.
This occurs when the number of iterations for model training is large. The solution suggested at [1] (setting a checkpoint directory) works for our scenario, and is the only solid solution we have for the moment. But as mentioned in [2], checkpointing add some overhead for spark operations, and requires some tuning based on the use case. Therefore, I'm not sure is it a good idea to enable checkpointing in ML, as it would affect DAS's performance. (This checkpointing is done for the Spark Context, and it is shared by both ML and DAS) Other option would be to, set checkpointing at the start of the Recommendation algorithm, and once the model is trained, then unset checkpointing. Since we are encountering this issue only at this particular algorithm, it is not needed to be done for any other algorithm. Would like to know what would be the best approach? [1] https://issues.apache.org/jira/browse/SPARK-13546 [2] http://spark.apache.org/docs/1.6.2/streaming-programming-guide.html#checkpointing *Stack Trace:* Caused by: java.lang.StackOverflowError at java.io.ObjectInputStream$BlockDataInputStream.peekByte(ObjectInputStream.java:2606) at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1506) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1774) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at scala.collection.immutable.$colon$colon.readObject(List.scala:362) at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1058) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1900) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at scala.collection.immutable.$colon$colon.readObject(List.scala:366) at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1058) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1900) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at scala.collection.immutable.$colon$colon.readObject(List.scala:362) at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1058) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1900) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at scala.collection.immutable.$colon$colon.readObject(List.scala:362) at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:497) at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1058) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1900) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:2000) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1924) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1801) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371) at scala.collection.immutable.$colon$colon.readObject(List.scala:362) at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) Regards, Supun -- *Supun Sethunga* Senior Software Engineer WSO2, Inc. http://wso2.com/ lean | enterprise | middleware Mobile : +94 716546324 Blog: http://supunsetunga.blogspot.com
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