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author | Reynold Xin <rxin@databricks.com> | 2015-02-08 18:56:51 -0800 |
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committer | Reynold Xin <rxin@databricks.com> | 2015-02-08 18:56:51 -0800 |
commit | a052ed42501fee3641348337505b6176426653c4 (patch) | |
tree | e708efe88401e54d61374b20e588b266c7836050 /sql/core | |
parent | 56aff4bd6c7c9d18f4f962025708f20a4a82dcf0 (diff) | |
download | spark-a052ed42501fee3641348337505b6176426653c4.tar.gz spark-a052ed42501fee3641348337505b6176426653c4.tar.bz2 spark-a052ed42501fee3641348337505b6176426653c4.zip |
[SPARK-5643][SQL] Add a show method to print the content of a DataFrame in tabular format.
An example:
```
year month AVG('Adj Close) MAX('Adj Close)
1980 12 0.503218 0.595103
1981 01 0.523289 0.570307
1982 02 0.436504 0.475256
1983 03 0.410516 0.442194
1984 04 0.450090 0.483521
```
Author: Reynold Xin <rxin@databricks.com>
Closes #4416 from rxin/SPARK-5643 and squashes the following commits:
d0e0d6e [Reynold Xin] [SQL] Minor update to data source and statistics documentation.
269da83 [Reynold Xin] Updated isLocal comment.
2cf3c27 [Reynold Xin] Moved logic into optimizer.
1a04d8b [Reynold Xin] [SPARK-5643][SQL] Add a show method to print the content of a DataFrame in columnar format.
Diffstat (limited to 'sql/core')
5 files changed, 72 insertions, 18 deletions
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala b/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala index 8ad6526f87..17ea3cde8e 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/DataFrame.scala @@ -102,7 +102,7 @@ trait DataFrame extends RDDApi[Row] { * }}} */ @scala.annotation.varargs - def toDataFrame(colName: String, colNames: String*): DataFrame + def toDataFrame(colNames: String*): DataFrame /** Returns the schema of this [[DataFrame]]. */ def schema: StructType @@ -117,6 +117,25 @@ trait DataFrame extends RDDApi[Row] { def printSchema(): Unit /** + * Returns true if the `collect` and `take` methods can be run locally + * (without any Spark executors). + */ + def isLocal: Boolean + + /** + * Displays the [[DataFrame]] in a tabular form. For example: + * {{{ + * year month AVG('Adj Close) MAX('Adj Close) + * 1980 12 0.503218 0.595103 + * 1981 01 0.523289 0.570307 + * 1982 02 0.436504 0.475256 + * 1983 03 0.410516 0.442194 + * 1984 04 0.450090 0.483521 + * }}} + */ + def show(): Unit + + /** * Cartesian join with another [[DataFrame]]. * * Note that cartesian joins are very expensive without an extra filter that can be pushed down. diff --git a/sql/core/src/main/scala/org/apache/spark/sql/DataFrameImpl.scala b/sql/core/src/main/scala/org/apache/spark/sql/DataFrameImpl.scala index 789bcf6184..fa05a5dcac 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/DataFrameImpl.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/DataFrameImpl.scala @@ -90,14 +90,13 @@ private[sql] class DataFrameImpl protected[sql]( } } - override def toDataFrame(colName: String, colNames: String*): DataFrame = { - val newNames = colName +: colNames - require(schema.size == newNames.size, + override def toDataFrame(colNames: String*): DataFrame = { + require(schema.size == colNames.size, "The number of columns doesn't match.\n" + "Old column names: " + schema.fields.map(_.name).mkString(", ") + "\n" + - "New column names: " + newNames.mkString(", ")) + "New column names: " + colNames.mkString(", ")) - val newCols = schema.fieldNames.zip(newNames).map { case (oldName, newName) => + val newCols = schema.fieldNames.zip(colNames).map { case (oldName, newName) => apply(oldName).as(newName) } select(newCols :_*) @@ -113,6 +112,38 @@ private[sql] class DataFrameImpl protected[sql]( override def printSchema(): Unit = println(schema.treeString) + override def isLocal: Boolean = { + logicalPlan.isInstanceOf[LocalRelation] + } + + override def show(): Unit = { + val data = take(20) + val numCols = schema.fieldNames.length + + // For cells that are beyond 20 characters, replace it with the first 17 and "..." + val rows: Seq[Seq[String]] = schema.fieldNames.toSeq +: data.map { row => + row.toSeq.map { cell => + val str = if (cell == null) "null" else cell.toString + if (str.length > 20) str.substring(0, 17) + "..." else str + } : Seq[String] + } + + // Compute the width of each column + val colWidths = Array.fill(numCols)(0) + for (row <- rows) { + for ((cell, i) <- row.zipWithIndex) { + colWidths(i) = math.max(colWidths(i), cell.length) + } + } + + // Pad the cells and print them + println(rows.map { row => + row.zipWithIndex.map { case (cell, i) => + String.format(s"%-${colWidths(i)}s", cell) + }.mkString(" ") + }.mkString("\n")) + } + override def join(right: DataFrame): DataFrame = { Join(logicalPlan, right.logicalPlan, joinType = Inner, None) } diff --git a/sql/core/src/main/scala/org/apache/spark/sql/IncomputableColumn.scala b/sql/core/src/main/scala/org/apache/spark/sql/IncomputableColumn.scala index 6043fb4dee..782f6e28ee 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/IncomputableColumn.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/IncomputableColumn.scala @@ -48,7 +48,7 @@ private[sql] class IncomputableColumn(protected[sql] val expr: Expression) exten protected[sql] override def logicalPlan: LogicalPlan = err() - override def toDataFrame(colName: String, colNames: String*): DataFrame = err() + override def toDataFrame(colNames: String*): DataFrame = err() override def schema: StructType = err() @@ -58,6 +58,10 @@ private[sql] class IncomputableColumn(protected[sql] val expr: Expression) exten override def printSchema(): Unit = err() + override def show(): Unit = err() + + override def isLocal: Boolean = false + override def join(right: DataFrame): DataFrame = err() override def join(right: DataFrame, joinExprs: Column): DataFrame = err() diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala index 66aed5d511..4dc506c21a 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala @@ -17,9 +17,6 @@ package org.apache.spark.sql.execution -import scala.collection.mutable.ArrayBuffer -import scala.reflect.runtime.universe.TypeTag - import org.apache.spark.{SparkEnv, HashPartitioner, SparkConf} import org.apache.spark.annotation.DeveloperApi import org.apache.spark.rdd.{RDD, ShuffledRDD} @@ -40,7 +37,7 @@ case class Project(projectList: Seq[NamedExpression], child: SparkPlan) extends @transient lazy val buildProjection = newMutableProjection(projectList, child.output) - def execute() = child.execute().mapPartitions { iter => + override def execute() = child.execute().mapPartitions { iter => val resuableProjection = buildProjection() iter.map(resuableProjection) } @@ -55,7 +52,7 @@ case class Filter(condition: Expression, child: SparkPlan) extends UnaryNode { @transient lazy val conditionEvaluator = newPredicate(condition, child.output) - def execute() = child.execute().mapPartitions { iter => + override def execute() = child.execute().mapPartitions { iter => iter.filter(conditionEvaluator) } } diff --git a/sql/core/src/main/scala/org/apache/spark/sql/sources/interfaces.scala b/sql/core/src/main/scala/org/apache/spark/sql/sources/interfaces.scala index a640ba57e0..5eecc303ef 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/sources/interfaces.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/sources/interfaces.scala @@ -87,13 +87,13 @@ trait CreatableRelationProvider { /** * ::DeveloperApi:: - * Represents a collection of tuples with a known schema. Classes that extend BaseRelation must - * be able to produce the schema of their data in the form of a [[StructType]] Concrete + * Represents a collection of tuples with a known schema. Classes that extend BaseRelation must + * be able to produce the schema of their data in the form of a [[StructType]]. Concrete * implementation should inherit from one of the descendant `Scan` classes, which define various * abstract methods for execution. * * BaseRelations must also define a equality function that only returns true when the two - * instances will return the same data. This equality function is used when determining when + * instances will return the same data. This equality function is used when determining when * it is safe to substitute cached results for a given relation. */ @DeveloperApi @@ -102,13 +102,16 @@ abstract class BaseRelation { def schema: StructType /** - * Returns an estimated size of this relation in bytes. This information is used by the planner + * Returns an estimated size of this relation in bytes. This information is used by the planner * to decided when it is safe to broadcast a relation and can be overridden by sources that * know the size ahead of time. By default, the system will assume that tables are too - * large to broadcast. This method will be called multiple times during query planning + * large to broadcast. This method will be called multiple times during query planning * and thus should not perform expensive operations for each invocation. + * + * Note that it is always better to overestimate size than underestimate, because underestimation + * could lead to execution plans that are suboptimal (i.e. broadcasting a very large table). */ - def sizeInBytes = sqlContext.conf.defaultSizeInBytes + def sizeInBytes: Long = sqlContext.conf.defaultSizeInBytes } /** |