Fix

docs/source/user-guide/configs.md

@@ -29,7 +29,7 @@ Comet provides the following configuration settings.
 | spark.comet.columnar.shuffle.async.enabled | Whether to enable asynchronous shuffle for Arrow-based shuffle. By default, this config is false. | false |
 | spark.comet.columnar.shuffle.async.max.thread.num | Maximum number of threads on an executor used for Comet async columnar shuffle. By default, this config is 100. This is the upper bound of total number of shuffle threads per executor. In other words, if the number of cores * the number of shuffle threads per task `spark.comet.columnar.shuffle.async.thread.num` is larger than this config. Comet will use this config as the number of shuffle threads per executor instead. | 100 |
 | spark.comet.columnar.shuffle.async.thread.num | Number of threads used for Comet async columnar shuffle per shuffle task. By default, this config is 3. Note that more threads means more memory requirement to buffer shuffle data before flushing to disk. Also, more threads may not always improve performance, and should be set based on the number of cores available. | 3 |
-| spark.comet.columnar.shuffle.enabled | Force Comet to only use columnar shuffle for CometScan and Spark regular operators. If this is enabled, Comet native shuffle will not be enabled but only Arrow shuffle. By default, this config is false. | false |
+| spark.comet.columnar.shuffle.enabled | Whether to enable Arrow-based columnar shuffle for Comet and Spark regular operators. If this is enabled, Comet prefers columnar shuffle than native shuffle. By default, this config is true. | true |
 | spark.comet.columnar.shuffle.memory.factor | Fraction of Comet memory to be allocated per executor process for Comet shuffle. Comet memory size is specified by `spark.comet.memoryOverhead` or calculated by `spark.comet.memory.overhead.factor` * `spark.executor.memory`. By default, this config is 1.0. | 1.0 |
 | spark.comet.debug.enabled | Whether to enable debug mode for Comet. By default, this config is false. When enabled, Comet will do additional checks for debugging purpose. For example, validating array when importing arrays from JVM at native side. Note that these checks may be expensive in performance and should only be enabled for debugging purpose. | false |
 | spark.comet.enabled | Whether to enable Comet extension for Spark. When this is turned on, Spark will use Comet to read Parquet data source. Note that to enable native vectorized execution, both this config and 'spark.comet.exec.enabled' need to be enabled. By default, this config is the value of the env var `ENABLE_COMET` if set, or true otherwise. | true |

spark/src/main/scala/org/apache/spark/sql/comet/plans/AliasAwareOutputExpression.scala

@@ -31,7 +31,7 @@ import org.apache.spark.sql.catalyst.trees.CurrentOrigin
 trait AliasAwareOutputExpression extends SQLConfHelper {
   // `SQLConf.EXPRESSION_PROJECTION_CANDIDATE_LIMIT` is Spark 3.4+ only.
   // Use a default value for now.
-  protected val aliasCandidateLimit =
+  protected val aliasCandidateLimit: Int =
     conf.getConfString("spark.sql.optimizer.expressionProjectionCandidateLimit", "100").toInt
   protected def outputExpressions: Seq[NamedExpression]