feat: Show user a more intuitive message when queries fall back to Sp…

…ark (#656) * update rustfmt to reorder imports * Enable fallback logging by default and use verbose format * update config guide * revert change * revert change * call generateVerboseExtendedInfo instead of generateExtendedInfo * improve log message * improve log message * format
apache · Jul 12, 2024 · b6d868c · b6d868c
1 parent 7783b39
commit b6d868c
Show file tree

Hide file tree

Showing 4 changed files with 11 additions and 14 deletions.
diff --git a/common/src/main/scala/org/apache/comet/CometConf.scala b/common/src/main/scala/org/apache/comet/CometConf.scala
@@ -286,9 +286,10 @@ object CometConf extends ShimCometConf {
     conf("spark.comet.explainFallback.enabled")
       .doc(
         "When this setting is enabled, Comet will provide logging explaining the reason(s) " +
-          "why a query stage cannot be executed natively.")
+          "why a query stage cannot be executed natively. Set this to false to " +
+          "reduce the amount of logging.")
       .booleanConf
-      .createWithDefault(false)
+      .createWithDefault(true)
 
   val COMET_BATCH_SIZE: ConfigEntry[Int] = conf("spark.comet.batchSize")
     .doc("The columnar batch size, i.e., the maximum number of rows that a batch can contain.")

diff --git a/docs/source/user-guide/configs.md b/docs/source/user-guide/configs.md
@@ -39,7 +39,7 @@ Comet provides the following configuration settings.
 | spark.comet.exec.shuffle.enabled | Whether to enable Comet native shuffle. By default, this config is false. Note that this requires setting 'spark.shuffle.manager' to 'org.apache.spark.sql.comet.execution.shuffle.CometShuffleManager'. 'spark.shuffle.manager' must be set before starting the Spark application and cannot be changed during the application. | false |
 | spark.comet.exec.shuffle.mode | The mode of Comet shuffle. This config is only effective if Comet shuffle is enabled. Available modes are 'native', 'jvm', and 'auto'. 'native' is for native shuffle which has best performance in general. 'jvm' is for jvm-based columnar shuffle which has higher coverage than native shuffle. 'auto' is for Comet to choose the best shuffle mode based on the query plan. By default, this config is 'jvm'. | jvm |
 | spark.comet.explain.verbose.enabled | When this setting is enabled, Comet will provide a verbose tree representation of the extended information. | false |
-| spark.comet.explainFallback.enabled | When this setting is enabled, Comet will provide logging explaining the reason(s) why a query stage cannot be executed natively. | false |
+| spark.comet.explainFallback.enabled | When this setting is enabled, Comet will provide logging explaining the reason(s) why a query stage cannot be executed natively. Set this to false to reduce the amount of logging. | true |
 | spark.comet.memory.overhead.factor | Fraction of executor memory to be allocated as additional non-heap memory per executor process for Comet. Default value is 0.2. | 0.2 |
 | spark.comet.memory.overhead.min | Minimum amount of additional memory to be allocated per executor process for Comet, in MiB. | 402653184b |
 | spark.comet.nativeLoadRequired | Whether to require Comet native library to load successfully when Comet is enabled. If not, Comet will silently fallback to Spark when it fails to load the native lib. Otherwise, an error will be thrown and the Spark job will be aborted. | false |

diff --git a/native/core/rustfmt.toml → native/rustfmt.toml b/native/core/rustfmt.toml → native/rustfmt.toml
diff --git a/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala b/spark/src/main/scala/org/apache/comet/CometSparkSessionExtensions.scala
@@ -850,17 +850,13 @@ class CometSparkSessionExtensions
         // if the plan cannot be run fully natively then explain why (when appropriate
         // config is enabled)
         if (CometConf.COMET_EXPLAIN_FALLBACK_ENABLED.get()) {
-          new ExtendedExplainInfo().extensionInfo(newPlan) match {
-            case reasons if reasons.size == 1 =>
-              logWarning(
-                "Comet cannot execute some parts of this plan natively " +
-                  s"because ${reasons.head}")
-            case reasons if reasons.size > 1 =>
-              logWarning(
-                "Comet cannot execute some parts of this plan natively" +
-                  s" because:\n\t- ${reasons.mkString("\n\t- ")}")
-            case _ =>
-            // no reasons recorded
+          val info = new ExtendedExplainInfo()
+          if (info.extensionInfo(newPlan).nonEmpty) {
+            logWarning(
+              "Comet cannot execute some parts of this plan natively " +
+                s"(set ${CometConf.COMET_EXPLAIN_FALLBACK_ENABLED.key}=false " +
+                "to disable this logging):\n" +
+                s"${info.generateVerboseExtendedInfo(newPlan)}")
           }
         }