diff --git a/docs/sql-programming-guide.md b/docs/sql-programming-guide.md index b2b007509c73..8022c5ecc243 100644 --- a/docs/sql-programming-guide.md +++ b/docs/sql-programming-guide.md @@ -14,10 +14,10 @@ title: Spark SQL Spark SQL allows relational queries expressed in SQL, HiveQL, or Scala to be executed using Spark. At the core of this component is a new type of RDD, -[SchemaRDD](api/scala/index.html#org.apache.spark.sql.SchemaRDD). SchemaRDDs are composed of +[DataFrame](api/scala/index.html#org.apache.spark.sql.DataFrame). DataFrames are composed of [Row](api/scala/index.html#org.apache.spark.sql.package@Row:org.apache.spark.sql.catalyst.expressions.Row.type) objects, along with -a schema that describes the data types of each column in the row. A SchemaRDD is similar to a table -in a traditional relational database. A SchemaRDD can be created from an existing RDD, a [Parquet](http://parquet.io) +a schema that describes the data types of each column in the row. A DataFrame is similar to a table +in a traditional relational database. A DataFrame can be created from an existing RDD, a [Parquet](http://parquet.io) file, a JSON dataset, or by running HiveQL against data stored in [Apache Hive](http://hive.apache.org/). All of the examples on this page use sample data included in the Spark distribution and can be run in the `spark-shell`. @@ -27,10 +27,10 @@ All of the examples on this page use sample data included in the Spark distribut
Spark SQL allows relational queries expressed in SQL or HiveQL to be executed using Spark. At the core of this component is a new type of RDD, -[JavaSchemaRDD](api/scala/index.html#org.apache.spark.sql.api.java.JavaSchemaRDD). JavaSchemaRDDs are composed of +[DataFrame](api/scala/index.html#org.apache.spark.sql.DataFrame). DataFrames are composed of [Row](api/scala/index.html#org.apache.spark.sql.api.java.Row) objects, along with -a schema that describes the data types of each column in the row. A JavaSchemaRDD is similar to a table -in a traditional relational database. A JavaSchemaRDD can be created from an existing RDD, a [Parquet](http://parquet.io) +a schema that describes the data types of each column in the row. A DataFrame is similar to a table +in a traditional relational database. A DataFrame can be created from an existing RDD, a [Parquet](http://parquet.io) file, a JSON dataset, or by running HiveQL against data stored in [Apache Hive](http://hive.apache.org/).
@@ -38,10 +38,10 @@ file, a JSON dataset, or by running HiveQL against data stored in [Apache Hive]( Spark SQL allows relational queries expressed in SQL or HiveQL to be executed using Spark. At the core of this component is a new type of RDD, -[SchemaRDD](api/python/pyspark.sql.SchemaRDD-class.html). SchemaRDDs are composed of +[DataFrame](api/python/pyspark.sql.html#pyspark.sql.DataFrame). DataFrames are composed of [Row](api/python/pyspark.sql.Row-class.html) objects, along with -a schema that describes the data types of each column in the row. A SchemaRDD is similar to a table -in a traditional relational database. A SchemaRDD can be created from an existing RDD, a [Parquet](http://parquet.io) +a schema that describes the data types of each column in the row. A DataFrame is similar to a table +in a traditional relational database. A DataFrame can be created from an existing RDD, a [Parquet](http://parquet.io) file, a JSON dataset, or by running HiveQL against data stored in [Apache Hive](http://hive.apache.org/). All of the examples on this page use sample data included in the Spark distribution and can be run in the `pyspark` shell. @@ -65,8 +65,8 @@ descendants. To create a basic SQLContext, all you need is a SparkContext. val sc: SparkContext // An existing SparkContext. val sqlContext = new org.apache.spark.sql.SQLContext(sc) -// createSchemaRDD is used to implicitly convert an RDD to a SchemaRDD. -import sqlContext.createSchemaRDD +// this is used to implicitly convert an RDD to a DataFrame. +import sqlContext.implicits._ {% endhighlight %} In addition to the basic SQLContext, you can also create a HiveContext, which provides a @@ -84,12 +84,12 @@ feature parity with a HiveContext.
The entry point into all relational functionality in Spark is the -[JavaSQLContext](api/scala/index.html#org.apache.spark.sql.api.java.JavaSQLContext) class, or one -of its descendants. To create a basic JavaSQLContext, all you need is a JavaSparkContext. +[SQLContext](api/scala/index.html#org.apache.spark.sql.api.SQLContext) class, or one +of its descendants. To create a basic SQLContext, all you need is a JavaSparkContext. {% highlight java %} JavaSparkContext sc = ...; // An existing JavaSparkContext. -JavaSQLContext sqlContext = new org.apache.spark.sql.api.java.JavaSQLContext(sc); +SQLContext sqlContext = new org.apache.spark.sql.SQLContext(sc); {% endhighlight %} In addition to the basic SQLContext, you can also create a HiveContext, which provides a strict @@ -138,21 +138,21 @@ default is "hiveql", though "sql" is also available. Since the HiveQL parser is # Data Sources -Spark SQL supports operating on a variety of data sources through the `SchemaRDD` interface. -A SchemaRDD can be operated on as normal RDDs and can also be registered as a temporary table. -Registering a SchemaRDD as a table allows you to run SQL queries over its data. This section -describes the various methods for loading data into a SchemaRDD. +Spark SQL supports operating on a variety of data sources through the `DataFrame` interface. +A DataFrame can be operated on as normal RDDs and can also be registered as a temporary table. +Registering a DataFrame as a table allows you to run SQL queries over its data. This section +describes the various methods for loading data into a DataFrame. ## RDDs -Spark SQL supports two different methods for converting existing RDDs into SchemaRDDs. The first +Spark SQL supports two different methods for converting existing RDDs into DataFrames. The first method uses reflection to infer the schema of an RDD that contains specific types of objects. This reflection based approach leads to more concise code and works well when you already know the schema while writing your Spark application. -The second method for creating SchemaRDDs is through a programmatic interface that allows you to +The second method for creating DataFrames is through a programmatic interface that allows you to construct a schema and then apply it to an existing RDD. While this method is more verbose, it allows -you to construct SchemaRDDs when the columns and their types are not known until runtime. +you to construct DataFrames when the columns and their types are not known until runtime. ### Inferring the Schema Using Reflection
@@ -160,17 +160,17 @@ you to construct SchemaRDDs when the columns and their types are not known until
The Scala interaface for Spark SQL supports automatically converting an RDD containing case classes -to a SchemaRDD. The case class +to a DataFrame. The case class defines the schema of the table. The names of the arguments to the case class are read using reflection and become the names of the columns. Case classes can also be nested or contain complex -types such as Sequences or Arrays. This RDD can be implicitly converted to a SchemaRDD and then be +types such as Sequences or Arrays. This RDD can be implicitly converted to a DataFrame and then be registered as a table. Tables can be used in subsequent SQL statements. {% highlight scala %} // sc is an existing SparkContext. val sqlContext = new org.apache.spark.sql.SQLContext(sc) -// createSchemaRDD is used to implicitly convert an RDD to a SchemaRDD. -import sqlContext.createSchemaRDD +// this is used to implicitly convert an RDD to a DataFrame. +import sqlContext.implicits._ // Define the schema using a case class. // Note: Case classes in Scala 2.10 can support only up to 22 fields. To work around this limit, @@ -184,7 +184,7 @@ people.registerTempTable("people") // SQL statements can be run by using the sql methods provided by sqlContext. val teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19") -// The results of SQL queries are SchemaRDDs and support all the normal RDD operations. +// The results of SQL queries are DataFrames and support all the normal RDD operations. // The columns of a row in the result can be accessed by ordinal. teenagers.map(t => "Name: " + t(0)).collect().foreach(println) {% endhighlight %} @@ -194,7 +194,7 @@ teenagers.map(t => "Name: " + t(0)).collect().foreach(println)
Spark SQL supports automatically converting an RDD of [JavaBeans](http://stackoverflow.com/questions/3295496/what-is-a-javabean-exactly) -into a Schema RDD. The BeanInfo, obtained using reflection, defines the schema of the table. +into a DataFrame. The BeanInfo, obtained using reflection, defines the schema of the table. Currently, Spark SQL does not support JavaBeans that contain nested or contain complex types such as Lists or Arrays. You can create a JavaBean by creating a class that implements Serializable and has getters and setters for all of its fields. @@ -230,7 +230,7 @@ for the JavaBean. {% highlight java %} // sc is an existing JavaSparkContext. -JavaSQLContext sqlContext = new org.apache.spark.sql.api.java.JavaSQLContext(sc); +SQLContext sqlContext = new org.apache.spark.sql.SQLContext(sc); // Load a text file and convert each line to a JavaBean. JavaRDD people = sc.textFile("examples/src/main/resources/people.txt").map( @@ -247,13 +247,13 @@ JavaRDD people = sc.textFile("examples/src/main/resources/people.txt").m }); // Apply a schema to an RDD of JavaBeans and register it as a table. -JavaSchemaRDD schemaPeople = sqlContext.createDataFrame(people, Person.class); +DataFrame schemaPeople = sqlContext.createDataFrame(people, Person.class); schemaPeople.registerTempTable("people"); // SQL can be run over RDDs that have been registered as tables. -JavaSchemaRDD teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19") +DataFrame teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19") -// The results of SQL queries are SchemaRDDs and support all the normal RDD operations. +// The results of SQL queries are DataFrames and support all the normal RDD operations. // The columns of a row in the result can be accessed by ordinal. List teenagerNames = teenagers.map(new Function() { public String call(Row row) { @@ -267,7 +267,7 @@ List teenagerNames = teenagers.map(new Function() {
-Spark SQL can convert an RDD of Row objects to a SchemaRDD, inferring the datatypes. Rows are constructed by passing a list of +Spark SQL can convert an RDD of Row objects to a DataFrame, inferring the datatypes. Rows are constructed by passing a list of key/value pairs as kwargs to the Row class. The keys of this list define the column names of the table, and the types are inferred by looking at the first row. Since we currently only look at the first row, it is important that there is no missing data in the first row of the RDD. In future versions we @@ -284,11 +284,11 @@ lines = sc.textFile("examples/src/main/resources/people.txt") parts = lines.map(lambda l: l.split(",")) people = parts.map(lambda p: Row(name=p[0], age=int(p[1]))) -# Infer the schema, and register the SchemaRDD as a table. +# Infer the schema, and register the DataFrame as a table. schemaPeople = sqlContext.inferSchema(people) schemaPeople.registerTempTable("people") -# SQL can be run over SchemaRDDs that have been registered as a table. +# SQL can be run over DataFrames that have been registered as a table. teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19") # The results of SQL queries are RDDs and support all the normal RDD operations. @@ -310,7 +310,7 @@ for teenName in teenNames.collect(): When case classes cannot be defined ahead of time (for example, the structure of records is encoded in a string, or a text dataset will be parsed and fields will be projected differently for different users), -a `SchemaRDD` can be created programmatically with three steps. +a `DataFrame` can be created programmatically with three steps. 1. Create an RDD of `Row`s from the original RDD; 2. Create the schema represented by a `StructType` matching the structure of @@ -341,15 +341,15 @@ val schema = val rowRDD = people.map(_.split(",")).map(p => Row(p(0), p(1).trim)) // Apply the schema to the RDD. -val peopleSchemaRDD = sqlContext.createDataFrame(rowRDD, schema) +val peopleDataFrame = sqlContext.createDataFrame(rowRDD, schema) -// Register the SchemaRDD as a table. -peopleSchemaRDD.registerTempTable("people") +// Register the DataFrames as a table. +peopleDataFrame.registerTempTable("people") // SQL statements can be run by using the sql methods provided by sqlContext. val results = sqlContext.sql("SELECT name FROM people") -// The results of SQL queries are SchemaRDDs and support all the normal RDD operations. +// The results of SQL queries are DataFrames and support all the normal RDD operations. // The columns of a row in the result can be accessed by ordinal. results.map(t => "Name: " + t(0)).collect().foreach(println) {% endhighlight %} @@ -362,13 +362,13 @@ results.map(t => "Name: " + t(0)).collect().foreach(println) When JavaBean classes cannot be defined ahead of time (for example, the structure of records is encoded in a string, or a text dataset will be parsed and fields will be projected differently for different users), -a `SchemaRDD` can be created programmatically with three steps. +a `DataFrame` can be created programmatically with three steps. 1. Create an RDD of `Row`s from the original RDD; 2. Create the schema represented by a `StructType` matching the structure of `Row`s in the RDD created in Step 1. 3. Apply the schema to the RDD of `Row`s via `createDataFrame` method provided -by `JavaSQLContext`. +by `SQLContext`. For example: {% highlight java %} @@ -381,7 +381,7 @@ import org.apache.spark.sql.api.java.StructField import org.apache.spark.sql.api.java.Row // sc is an existing JavaSparkContext. -JavaSQLContext sqlContext = new org.apache.spark.sql.api.java.JavaSQLContext(sc); +SQLContext sqlContext = new org.apache.spark.sql.SQLContext(sc); // Load a text file and convert each line to a JavaBean. JavaRDD people = sc.textFile("examples/src/main/resources/people.txt"); @@ -406,15 +406,15 @@ JavaRDD rowRDD = people.map( }); // Apply the schema to the RDD. -JavaSchemaRDD peopleSchemaRDD = sqlContext.createDataFrame(rowRDD, schema); +DataFrame peopleDataFrame = sqlContext.createDataFrame(rowRDD, schema); -// Register the SchemaRDD as a table. -peopleSchemaRDD.registerTempTable("people"); +// Register the DataFrame as a table. +peopleDataFrame.registerTempTable("people"); // SQL can be run over RDDs that have been registered as tables. -JavaSchemaRDD results = sqlContext.sql("SELECT name FROM people"); +DataFrame results = sqlContext.sql("SELECT name FROM people"); -// The results of SQL queries are SchemaRDDs and support all the normal RDD operations. +// The results of SQL queries are DataFrames and support all the normal RDD operations. // The columns of a row in the result can be accessed by ordinal. List names = results.map(new Function() { public String call(Row row) { @@ -431,7 +431,7 @@ List names = results.map(new Function() { When a dictionary of kwargs cannot be defined ahead of time (for example, the structure of records is encoded in a string, or a text dataset will be parsed and fields will be projected differently for different users), -a `SchemaRDD` can be created programmatically with three steps. +a `DataFrame` can be created programmatically with three steps. 1. Create an RDD of tuples or lists from the original RDD; 2. Create the schema represented by a `StructType` matching the structure of @@ -460,10 +460,10 @@ schema = StructType(fields) # Apply the schema to the RDD. schemaPeople = sqlContext.createDataFrame(people, schema) -# Register the SchemaRDD as a table. +# Register the DataFrame as a table. schemaPeople.registerTempTable("people") -# SQL can be run over SchemaRDDs that have been registered as a table. +# SQL can be run over DataFrames that have been registered as a table. results = sqlContext.sql("SELECT name FROM people") # The results of SQL queries are RDDs and support all the normal RDD operations. @@ -493,16 +493,16 @@ Using the data from the above example: {% highlight scala %} // sqlContext from the previous example is used in this example. -// createSchemaRDD is used to implicitly convert an RDD to a SchemaRDD. -import sqlContext.createSchemaRDD +// This is used to implicitly convert an RDD to a DataFrame. +import sqlContext.implicits._ val people: RDD[Person] = ... // An RDD of case class objects, from the previous example. -// The RDD is implicitly converted to a SchemaRDD by createSchemaRDD, allowing it to be stored using Parquet. +// The RDD is implicitly converted to a DataFrame by implicits, allowing it to be stored using Parquet. people.saveAsParquetFile("people.parquet") // Read in the parquet file created above. Parquet files are self-describing so the schema is preserved. -// The result of loading a Parquet file is also a SchemaRDD. +// The result of loading a Parquet file is also a DataFrame. val parquetFile = sqlContext.parquetFile("people.parquet") //Parquet files can also be registered as tables and then used in SQL statements. @@ -518,18 +518,18 @@ teenagers.map(t => "Name: " + t(0)).collect().foreach(println) {% highlight java %} // sqlContext from the previous example is used in this example. -JavaSchemaRDD schemaPeople = ... // The JavaSchemaRDD from the previous example. +DataFrame schemaPeople = ... // The DataFrame from the previous example. -// JavaSchemaRDDs can be saved as Parquet files, maintaining the schema information. +// DataFrames can be saved as Parquet files, maintaining the schema information. schemaPeople.saveAsParquetFile("people.parquet"); // Read in the Parquet file created above. Parquet files are self-describing so the schema is preserved. -// The result of loading a parquet file is also a JavaSchemaRDD. -JavaSchemaRDD parquetFile = sqlContext.parquetFile("people.parquet"); +// The result of loading a parquet file is also a DataFrame. +DataFrame parquetFile = sqlContext.parquetFile("people.parquet"); //Parquet files can also be registered as tables and then used in SQL statements. parquetFile.registerTempTable("parquetFile"); -JavaSchemaRDD teenagers = sqlContext.sql("SELECT name FROM parquetFile WHERE age >= 13 AND age <= 19"); +DataFrame teenagers = sqlContext.sql("SELECT name FROM parquetFile WHERE age >= 13 AND age <= 19"); List teenagerNames = teenagers.map(new Function() { public String call(Row row) { return "Name: " + row.getString(0); @@ -544,13 +544,13 @@ List teenagerNames = teenagers.map(new Function() { {% highlight python %} # sqlContext from the previous example is used in this example. -schemaPeople # The SchemaRDD from the previous example. +schemaPeople # The DataFrame from the previous example. -# SchemaRDDs can be saved as Parquet files, maintaining the schema information. +# DataFrames can be saved as Parquet files, maintaining the schema information. schemaPeople.saveAsParquetFile("people.parquet") # Read in the Parquet file created above. Parquet files are self-describing so the schema is preserved. -# The result of loading a parquet file is also a SchemaRDD. +# The result of loading a parquet file is also a DataFrame. parquetFile = sqlContext.parquetFile("people.parquet") # Parquet files can also be registered as tables and then used in SQL statements. @@ -629,7 +629,7 @@ Configuration of Parquet can be done using the `setConf` method on SQLContext or
-Spark SQL can automatically infer the schema of a JSON dataset and load it as a SchemaRDD. +Spark SQL can automatically infer the schema of a JSON dataset and load it as a DataFrame. This conversion can be done using one of two methods in a SQLContext: * `jsonFile` - loads data from a directory of JSON files where each line of the files is a JSON object. @@ -646,7 +646,7 @@ val sqlContext = new org.apache.spark.sql.SQLContext(sc) // A JSON dataset is pointed to by path. // The path can be either a single text file or a directory storing text files. val path = "examples/src/main/resources/people.json" -// Create a SchemaRDD from the file(s) pointed to by path +// Create a DataFrame from the file(s) pointed to by path val people = sqlContext.jsonFile(path) // The inferred schema can be visualized using the printSchema() method. @@ -655,13 +655,13 @@ people.printSchema() // |-- age: integer (nullable = true) // |-- name: string (nullable = true) -// Register this SchemaRDD as a table. +// Register this DataFrame as a table. people.registerTempTable("people") // SQL statements can be run by using the sql methods provided by sqlContext. val teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19") -// Alternatively, a SchemaRDD can be created for a JSON dataset represented by +// Alternatively, a DataFrame can be created for a JSON dataset represented by // an RDD[String] storing one JSON object per string. val anotherPeopleRDD = sc.parallelize( """{"name":"Yin","address":{"city":"Columbus","state":"Ohio"}}""" :: Nil) @@ -671,8 +671,8 @@ val anotherPeople = sqlContext.jsonRDD(anotherPeopleRDD)
-Spark SQL can automatically infer the schema of a JSON dataset and load it as a JavaSchemaRDD. -This conversion can be done using one of two methods in a JavaSQLContext : +Spark SQL can automatically infer the schema of a JSON dataset and load it as a DataFrame. +This conversion can be done using one of two methods in a SQLContext : * `jsonFile` - loads data from a directory of JSON files where each line of the files is a JSON object. * `jsonRDD` - loads data from an existing RDD where each element of the RDD is a string containing a JSON object. @@ -683,13 +683,13 @@ a regular multi-line JSON file will most often fail. {% highlight java %} // sc is an existing JavaSparkContext. -JavaSQLContext sqlContext = new org.apache.spark.sql.api.java.JavaSQLContext(sc); +SQLContext sqlContext = new org.apache.spark.sql.SQLContext(sc); // A JSON dataset is pointed to by path. // The path can be either a single text file or a directory storing text files. String path = "examples/src/main/resources/people.json"; -// Create a JavaSchemaRDD from the file(s) pointed to by path -JavaSchemaRDD people = sqlContext.jsonFile(path); +// Create a DataFrame from the file(s) pointed to by path +DataFrame people = sqlContext.jsonFile(path); // The inferred schema can be visualized using the printSchema() method. people.printSchema(); @@ -697,23 +697,23 @@ people.printSchema(); // |-- age: integer (nullable = true) // |-- name: string (nullable = true) -// Register this JavaSchemaRDD as a table. +// Register this DataFrame as a table. people.registerTempTable("people"); // SQL statements can be run by using the sql methods provided by sqlContext. -JavaSchemaRDD teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19"); +DataFrame teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19"); -// Alternatively, a JavaSchemaRDD can be created for a JSON dataset represented by +// Alternatively, a DataFrame can be created for a JSON dataset represented by // an RDD[String] storing one JSON object per string. List jsonData = Arrays.asList( "{\"name\":\"Yin\",\"address\":{\"city\":\"Columbus\",\"state\":\"Ohio\"}}"); JavaRDD anotherPeopleRDD = sc.parallelize(jsonData); -JavaSchemaRDD anotherPeople = sqlContext.jsonRDD(anotherPeopleRDD); +DataFrame anotherPeople = sqlContext.jsonRDD(anotherPeopleRDD); {% endhighlight %}
-Spark SQL can automatically infer the schema of a JSON dataset and load it as a SchemaRDD. +Spark SQL can automatically infer the schema of a JSON dataset and load it as a DataFrame. This conversion can be done using one of two methods in a SQLContext: * `jsonFile` - loads data from a directory of JSON files where each line of the files is a JSON object. @@ -731,7 +731,7 @@ sqlContext = SQLContext(sc) # A JSON dataset is pointed to by path. # The path can be either a single text file or a directory storing text files. path = "examples/src/main/resources/people.json" -# Create a SchemaRDD from the file(s) pointed to by path +# Create a DataFrame from the file(s) pointed to by path people = sqlContext.jsonFile(path) # The inferred schema can be visualized using the printSchema() method. @@ -740,13 +740,13 @@ people.printSchema() # |-- age: integer (nullable = true) # |-- name: string (nullable = true) -# Register this SchemaRDD as a table. +# Register this DataFrame as a table. people.registerTempTable("people") # SQL statements can be run by using the sql methods provided by sqlContext. teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19") -# Alternatively, a SchemaRDD can be created for a JSON dataset represented by +# Alternatively, a DataFrame can be created for a JSON dataset represented by # an RDD[String] storing one JSON object per string. anotherPeopleRDD = sc.parallelize([ '{"name":"Yin","address":{"city":"Columbus","state":"Ohio"}}']) @@ -792,14 +792,14 @@ sqlContext.sql("FROM src SELECT key, value").collect().foreach(println)
-When working with Hive one must construct a `JavaHiveContext`, which inherits from `JavaSQLContext`, and +When working with Hive one must construct a `HiveContext`, which inherits from `SQLContext`, and adds support for finding tables in the MetaStore and writing queries using HiveQL. In addition to -the `sql` method a `JavaHiveContext` also provides an `hql` methods, which allows queries to be +the `sql` method a `HiveContext` also provides an `hql` methods, which allows queries to be expressed in HiveQL. {% highlight java %} // sc is an existing JavaSparkContext. -JavaHiveContext sqlContext = new org.apache.spark.sql.hive.api.java.HiveContext(sc); +HiveContext sqlContext = new org.apache.spark.sql.hive.HiveContext(sc); sqlContext.sql("CREATE TABLE IF NOT EXISTS src (key INT, value STRING)"); sqlContext.sql("LOAD DATA LOCAL INPATH 'examples/src/main/resources/kv1.txt' INTO TABLE src"); @@ -841,7 +841,7 @@ turning on some experimental options. ## Caching Data In Memory -Spark SQL can cache tables using an in-memory columnar format by calling `sqlContext.cacheTable("tableName")` or `schemaRDD.cache()`. +Spark SQL can cache tables using an in-memory columnar format by calling `sqlContext.cacheTable("tableName")` or `dataFrame.cache()`. Then Spark SQL will scan only required columns and will automatically tune compression to minimize memory usage and GC pressure. You can call `sqlContext.uncacheTable("tableName")` to remove the table from memory. @@ -1161,7 +1161,7 @@ teenagers.map(t => "Name: " + t(0)).collect().foreach(println) The DSL uses Scala symbols to represent columns in the underlying table, which are identifiers prefixed with a tick (`'`). Implicit conversions turn these symbols into expressions that are evaluated by the SQL execution engine. A full list of the functions supported can be found in the -[ScalaDoc](api/scala/index.html#org.apache.spark.sql.SchemaRDD). +[ScalaDoc](api/scala/index.html#org.apache.spark.sql.DataFrame).