viirya commented on code in PR #170: URL: https://github.com/apache/arrow-datafusion-comet/pull/170#discussion_r1514946079
########## DEBUGGING.md: ########## @@ -94,3 +94,62 @@ https://mail.openjdk.org/pipermail/hotspot-dev/2019-September/039429.html Detecting the debugger https://stackoverflow.com/questions/5393403/can-a-java-application-detect-that-a-debugger-is-attached#:~:text=No.,to%20let%20your%20app%20continue.&text=I%20know%20that%20those%20are,meant%20with%20my%20first%20phrase). + +# Verbose debug +By default, Comet outputs the exception details specific for Comet. + +```scala +scala> spark.sql("my_failing_query").show(false) + +24/03/05 17:00:07 ERROR Executor: Exception in task 0.0 in stage 0.0 (TID 0)/ 1] +org.apache.comet.CometNativeException: Internal error: MIN/MAX is not expected to receive scalars of incompatible types (Date32("NULL"), Int32(15901)). +This was likely caused by a bug in DataFusion's code and we would welcome that you file an bug report in our issue tracker + at org.apache.comet.Native.executePlan(Native Method) + at org.apache.comet.CometExecIterator.executeNative(CometExecIterator.scala:65) + at org.apache.comet.CometExecIterator.getNextBatch(CometExecIterator.scala:111) + at org.apache.comet.CometExecIterator.hasNext(CometExecIterator.scala:126) + +``` + +There is a verbose exception option by leveraging Datafusion [backtraces](https://arrow.apache.org/datafusion/user-guide/example-usage.html#enable-backtraces) +This option allows to append native Datafusion stacktrace to the original error message. +To enable this option with Comet it is needed to include `backtrace` feature in [Cargo.toml](https://github.com/apache/arrow-datafusion-comet/blob/main/core/Cargo.toml) for Datafusion dependencies + +``` +datafusion-common = { version = "36.0.0", features = ["backtrace"] } +datafusion = { default-features = false, version = "36.0.0", features = ["unicode_expressions", "backtrace"] } +``` + +Then build the Comet as [described](https://github.com/apache/arrow-datafusion-comet/blob/main/README.md#getting-started) + +Start Comet with `RUST_BACKTRACE=1` + +```commandline +RUST_BACKTRACE=1 $SPARK_HOME/spark-shell --jars spark/target/comet-spark-spark3.4_2.12-0.1.0-SNAPSHOT.jar --conf spark.sql.extensions=org.apache.comet.CometSparkSessionExtensions --conf spark.comet.enabled=true --conf spark.comet.exec.enabled=true --conf spark.comet.exec.all.enabled=true +``` + +Get the expanded exception details +```scala +scala> spark.sql("my_failing_query").show(false) +24/03/05 17:00:49 ERROR Executor: Exception in task 0.0 in stage 0.0 (TID 0) +org.apache.comet.CometNativeException: Internal error: MIN/MAX is not expected to receive scalars of incompatible types (Date32("NULL"), Int32(15901)) + +backtrace: + 0: std::backtrace::Backtrace::create + 1: datafusion_physical_expr::aggregate::min_max::min + 2: <datafusion_physical_expr::aggregate::min_max::MinAccumulator as datafusion_expr::accumulator::Accumulator>::update_batch + 3: <futures_util::stream::stream::fuse::Fuse<S> as futures_core::stream::Stream>::poll_next + 4: comet::execution::jni_api::Java_org_apache_comet_Native_executePlan::{{closure}} + 5: _Java_org_apache_comet_Native_executePlan + ... +This was likely caused by a bug in DataFusion's code and we would welcome that you file an bug report in our issue tracker + at org.apache.comet.Native.executePlan(Native Method) +at org.apache.comet.CometExecIterator.executeNative(CometExecIterator.scala:65) +at org.apache.comet.CometExecIterator.getNextBatch(CometExecIterator.scala:111) +at org.apache.comet.CometExecIterator.hasNext(CometExecIterator.scala:126) + +... +``` +Note: +- The backtrace coverage in Datafusion is still improving. So there is a chance the error still not covered, feel free to file a [ticket](https://github.com/apache/arrow-datafusion/issues) +- The backtrace doesn't come for free and therefore intended for debugging purposes Review Comment: ```suggestion - The backtrace doesn't come for free and therefore intended for debugging purposes. ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
