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--- en:site:recherche:logiciels:sparqlwithspark:utility [13/09/2016 18:42]
hubert created
+++ en:site:recherche:logiciels:sparqlwithspark:utility [16/09/2016 23:05] (current)
hubert [Utilities]
@@ Line 1: / Line 1: @@
+{{indexmenu_n>9}}
 ====== Utilities ======
+=== Data loading utilities===
+<code scala>
+// TIMER
+def queryTimeDFIter(q: DataFrame, nbIter: Int): Unit = {
+  var l = new scala.collection.mutable.ArrayBuffer[Double](nbIter)
+  for( i <- 1 to nbIter) {
+    var start = java.lang.System.currentTimeMillis();
+    var c = q.count
+    var t = (java.lang.System.currentTimeMillis() - start).toDouble /1000
+    l.append(t)
+    println("")
+    println(s"Count=$c, Time= $t (s)")
+  }
+  val avg = l.reduce(_+_).toDouble/l.size
+  println(s"AVERAGE time for ${l.size} values is: $avg")
+}
+// define VPs to be loaded
+//-------------------------
+val nbP = dictP.count.toInt
+val r = (0 to nbP-1)
+// SPECIFY THE PARTITIONING : either default or subject based
+// ------------------------
+// Default partitioning (s,o)
+val VP2Random = r.map(i => (i, sqlContext.read.parquet(vpDir + "/p" + i).repartition(NB_FRAGMENTS) )).toMap
+// Partitioning by SUBJECT (s)
+val VP2 = r.map(i => (i, sqlContext.read.parquet(vpDir + "/p" + i).repartition(NB_FRAGMENTS, col("s")) )).toMap
+// load VP sizes
+val VP2Size = sqlContext.read.parquet(vpDir + "/size").collect.map(r => (r.getLong(0).toInt, r.getLong(1))).toMap
+val nameSpace = Map(
+"dc" -> "http://purl.org/dc/terms/",
+"foaf" -> "http://xmlns.com/foaf/",
+"gr" -> "http://purl.org/goodrelations/",
+"gn" -> "http://www.geonames.org/ontology#",
+"mo" -> "http://purl.org/ontology/mo/",
+"og" -> "http://ogp.me/ns#",
+"rev" -> "http://purl.org/stuff/rev#",
+"rdf" -> "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
+"rdfs" -> "http://www.w3.org/2000/01/rdf-schema#",
+"sorg" -> "http://schema.org/",
+"wsdbm" -> "http://db.uwaterloo.ca/~galuc/wsdbm/")
+def getIdP(prefix: String, p: String):Int =  {
+  val ns = nameSpace.get(prefix).get
+  val full = ns + p
+  return dictP.where(s"p = '<$full>'").take(1).head.getLong(1).toInt
+}
+def getIdSO(prefix: String, s: String): Long =  {
+  val ns = nameSpace.get(prefix).get
+  val full = ns + s
+  return dictSO.where(s"so = '<$full>'").take(1).head.getLong(1)
+}
+</code>
+=== QUERY utilities ===
+<code scala>
+case class v(n:Int)
+def sparqlSplit(sparql:  List[(Any, String, Any)]): List[(Any, (String, String), Any)] = {
+  return sparql.map{case(s,p,o)=>(s,p.split(":"),o)}.map{case(s,p,o)=>(s,(p(0), p(1)), o)}
+}
+//persist VPs accessed by a query q
+def persistQueryVP(q: List[(Any, (String, String), Any)], vps: Map[Int,org.apache.spark.sql.DataFrame])={
+q.map{case(_,(ns,p),_) => vps(getIdP(ns, p)).persist().count}
+}
+// encode properties and literals in a query
+def sparqlEncode(splittedSparql: List[(Any, (String, String), Any)]): List[(Any, Int, Any)]  = {
+  return splittedSparql.map{ case (s,(ns,p),o) =>
+                          val idP = getIdP(ns, p)
+                          (s, o) match {
+                            case(v(a), v(b))=> (v(a), idP, v(b))
+                            case(lit:String, v(b)) => { val idLit = getIdSO(lit.split(":")(0), lit.split(":")(1))
+                                                        (idLit, idP, v(b))}
+                            case(v(a), lit:String)  => { val idLit = getIdSO(lit.split(":")(0), lit.split(":")(1))
+                                                        (v(a), idP, idLit)}
+}}}
+// generate selection operator for each triple pattern
+def tpOperators(encodedQuery: List[(Any, Int, Any)], d: Map[Int, DataFrame]) =
+encodedQuery.map{ case(v(a), p, v(b))=> ( (v(a), p, v(b)), d(p).withColumnRenamed("o", s"v$b"))
+                        case(lit,  p, v(b))=> ( (lit , p, v(b)), d(p).where(s"s=$lit").select("o").withColumnRenamed("o", s"v$b"))
+                        case(v(a), p, lit) => ( (v(a), p, lit ), d(p).where(s"o=$lit").select("s"))
+                      }
+</code>
+back to   [[en:site:recherche:logiciels:sparqlwithspark| SPARQL Query Processing with Apache Spark]]

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