public static void Main(string[] args)
{
// Create Spark session.
SparkSession spark = SparkSession
.Builder()
.AppName("Hyperspace example")
.Config("spark.some.config.option", "some-value")
.GetOrCreate();
// Sample department records.
var departments = new List <GenericRow>()
{
new GenericRow(new object[] { 10, "Accounting", "New York" }),
new GenericRow(new object[] { 20, "Research", "Dallas" }),
new GenericRow(new object[] { 30, "Sales", "Chicago" }),
new GenericRow(new object[] { 40, "Operations", "Boston" })
};
// Sample employee records.
var employees = new List <GenericRow>()
{
new GenericRow(new object[] { 7369, "SMITH", 20 }),
new GenericRow(new object[] { 7499, "ALLEN", 30 }),
new GenericRow(new object[] { 7521, "WARD", 30 }),
new GenericRow(new object[] { 7566, "JONES", 20 }),
new GenericRow(new object[] { 7698, "BLAKE", 30 }),
new GenericRow(new object[] { 7782, "CLARK", 10 }),
new GenericRow(new object[] { 7788, "SCOTT", 20 }),
new GenericRow(new object[] { 7839, "KING", 10 }),
new GenericRow(new object[] { 7844, "TURNER", 30 }),
new GenericRow(new object[] { 7876, "ADAMS", 20 }),
new GenericRow(new object[] { 7900, "JAMES", 30 }),
new GenericRow(new object[] { 7934, "MILLER", 10 }),
new GenericRow(new object[] { 7902, "FORD", 20 }),
new GenericRow(new object[] { 7654, "MARTIN", 30 })
};
// Save example data records as Parquet.
string deptLocation = "departments";
spark.CreateDataFrame(departments, new StructType(new List <StructField>()
{
new StructField("deptId", new IntegerType()),
new StructField("deptName", new StringType()),
new StructField("location", new StringType())
}))
.Write()
.Mode("overwrite")
.Parquet(deptLocation);
string empLocation = "employees";
spark.CreateDataFrame(employees, new StructType(new List <StructField>()
{
new StructField("empId", new IntegerType()),
new StructField("empName", new StringType()),
new StructField("deptId", new IntegerType())
}))
.Write()
.Mode("overwrite")
.Parquet(empLocation);
// Create Hyperspace indexes.
var hyperspace = new Hyperspace(spark);
DataFrame deptDF = spark.Read().Parquet(deptLocation);
DataFrame empDF = spark.Read().Parquet(empLocation);
var deptIndexConfig = new IndexConfig(
"deptIndex",
new[] { "deptId" },
new[] { "deptName" });
var empIndexConfig = new IndexConfig("empIndex",
new[] { "deptId" },
new[] { "empName" });
hyperspace.CreateIndex(deptDF, deptIndexConfig);
hyperspace.CreateIndex(empDF, empIndexConfig);
// List all indexes.
hyperspace.Indexes().Show();
// Enable Hyperspace to leverage indexes.
spark.EnableHyperspace();
// Example of index usage for filtered selection.
DataFrame eqFilter = deptDF.Filter("deptId = 20").Select("deptName");
eqFilter.Show();
hyperspace.Explain(eqFilter, false);
// Example of index usage for join.
DataFrame eqJoin = empDF
.Join(deptDF, "deptId")
.Select(empDF.Col("empName"), deptDF.Col("deptName"));
eqJoin.Show();
hyperspace.Explain(eqJoin, false);
// Stop Spark session.
spark.Stop();
}