Add tutorial

Author: Sameer Axiomine <sameer@axiomine.com>

Closes #101 from sameeraxiomine/master.

README.md

@@ -332,4 +332,4 @@ directly:
 
 Version 0.4+ adds the DataSource API and JDBC, which is an entirely new API, so although this won't break
 code using the InputFormat directly, you may wish to make use of the new functionality to avoid performing
-<tt>UNLOAD</tt> queries manually.
+<tt>UNLOAD</tt> queries manually.

tutorial/SparkRedshiftTutorial.scala

@@ -0,0 +1,162 @@
+/*
+ * Copyright 2015 Databricks
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.databricks.spark.redshift.tutorial
+import org.apache.spark.{SparkConf,SparkContext}
+import org.apache.spark.sql.SaveMode
+import org.apache.spark.sql.SQLContext
+import org.apache.spark.sql.types.{StructType,StructField,DecimalType,IntegerType,LongType,StringType}
+
+
+/**
+ * Source code accompanying the spark-redshift tutorial.
+ * The following parameters need to be passed
+ * 1. AWS Access Key
+ * 2. AWS Secret Access Key
+ * 3. Redshift Database Name
+ * 4. Redshift UserId
+ * 5. Redshift Password
+ * 6. Redshift URL (Ex. swredshift.czac2vcs84ci.us-east-1.redshift.amazonaws.com:5439)
+ */
+object SparkRedshiftTutorial {
+  /*
+   * For Windows Users only
+   * 1. Download contents from link 
+   *      https://github.com/srccodes/hadoop-common-2.2.0-bin/archive/master.zip
+   * 2. Unzip the file in step 1 into your %HADOOP_HOME%/bin. 
+   * 3. pass System parameter -Dhadoop.home.dir=%HADOOP_HOME/bin  where %HADOOP_HOME 
+   *    must be an absolute not relative path
+   */
+
+  def main(args: Array[String]): Unit = {
+
+    if (args.length < 6) {
+      println("Needs 6 parameters only passed " + args.length)
+      println("parameters needed - $awsAccessKey $awsSecretKey $rsDbName $rsUser $rsPassword $rsURL")
+    }
+    val awsAccessKey = args(0)
+    val awsSecretKey = args(1)
+    val rsDbName = args(2)
+    val rsUser = args(3)
+    val rsPassword = args(4)
+    //Sample Redshift URL is swredshift.czac2vcs84ci.us-east-1.redshift.amazonaws.com:5439
+    val rsURL = args(5)
+    val jdbcURL = s"""jdbc:redshift://$rsURL/$rsDbName?user=$rsUser&password=$rsPassword"""
+    println(jdbcURL)
+    val sc = new SparkContext(new SparkConf().setAppName("SparkSQL").setMaster("local"))
+
+    val tempS3Dir = "s3n://redshift-spark/temp/"
+    sc.hadoopConfiguration.set("fs.s3n.awsAccessKeyId", awsAccessKey)
+    sc.hadoopConfiguration.set("fs.s3n.awsSecretAccessKey", awsSecretKey)
+
+    val sqlContext = new SQLContext(sc)
+
+    import sqlContext.implicits._
+
+    //Load from a table 
+    val eventsDF = sqlContext.read
+      .format("com.databricks.spark.redshift")
+      .option("url", jdbcURL)
+      .option("tempdir", tempS3Dir)
+      .option("dbtable", "event")
+      .load()
+    eventsDF.show()
+    eventsDF.printSchema()
+
+    //Load from a query 
+    val salesQuery = """SELECT salesid, listid, sellerid, buyerid, 
+                               eventid, dateid, qtysold, pricepaid, commission 
+                        FROM sales 
+                        ORDER BY saletime DESC LIMIT 10000"""
+    val salesDF = sqlContext.read
+      .format("com.databricks.spark.redshift")
+      .option("url", jdbcURL)
+      .option("tempdir", tempS3Dir)
+      .option("query", salesQuery)
+      .load()
+    salesDF.show()
+
+    val eventQuery = "SELECT * FROM event"
+    val eventDF = sqlContext.read
+      .format("com.databricks.spark.redshift")
+      .option("url", jdbcURL)
+      .option("tempdir", tempS3Dir)
+      .option("query", eventQuery)
+      .load()
+
+    /*
+     * Register 'event' table as temporary table 'myevent' 
+     * so that it can be queried via sqlContext.sql  
+     */
+    eventsDF.registerTempTable("myevent")
+
+    //Save to a Redshift table from a table registered in Spark
+
+    /*
+     * Create a new table redshiftevent after dropping any existing redshiftevent table
+     * and write event records with event id less than 1000
+     */
+    sqlContext.sql("SELECT * FROM myevent WHERE eventid<=1000").withColumnRenamed("eventid", "id")
+      .write.format("com.databricks.spark.redshift")
+      .option("url", jdbcURL)
+      .option("tempdir", tempS3Dir)
+      .option("dbtable", "redshiftevent")
+      .mode(SaveMode.Overwrite)
+      .save()
+
+    /*
+     * Append to an existing table redshiftevent if it exists or create a new one if it does not
+     * exist and write event records with event id greater than 1000
+     */
+    sqlContext.sql("SELECT * FROM myevent WHERE eventid>1000").withColumnRenamed("eventid", "id")
+      .write.format("com.databricks.spark.redshift")
+      .option("url", jdbcURL)
+      .option("tempdir", tempS3Dir)
+      .option("dbtable", "redshiftevent")
+      .mode(SaveMode.Append)
+      .save()
+
+    /** Demonstration of interoperability */
+    val salesAGGQuery = """SELECT sales.eventid AS id, SUM(qtysold) AS totalqty, SUM(pricepaid) AS salesamt
+                           FROM sales
+                           GROUP BY (sales.eventid)
+                           """
+    val salesAGGDF = sqlContext.read
+      .format("com.databricks.spark.redshift")
+      .option("url", jdbcURL)
+      .option("tempdir", tempS3Dir)
+      .option("query", salesAGGQuery)
+      .load()
+    salesAGGDF.registerTempTable("salesagg")
+
+    /*
+     * Join two DataFrame instances. Each could be sourced from any 
+     * compatible Data Source
+     */
+    val salesAGGDF2 = salesAGGDF.join(eventsDF, salesAGGDF("id") === eventsDF("eventid"))
+      .select("id", "eventname", "totalqty", "salesamt")
+
+    salesAGGDF2.registerTempTable("redshift_sales_agg")
+
+    sqlContext.sql("SELECT * FROM redshift_sales_agg")
+      .write.format("com.databricks.spark.redshift")
+      .option("url", jdbcURL)
+      .option("tempdir", tempS3Dir)
+      .option("dbtable", "redshift_sales_agg")
+      .mode(SaveMode.Overwrite)
+      .save()
+  }
+}