From d5d60c5a2ec20896a824ba71a11c0e8c2d78a5ca Mon Sep 17 00:00:00 2001
From: Federico Igne <federico.igne@cs.ox.ac.uk>
Date: Mon, 1 Nov 2021 16:58:09 +0000
Subject: Drop filtering tuple table when done with a query

This avoids running out of memory on RDFox side when executing a use
amount of queries.
---
 src/main/scala/uk/ac/ox/cs/rsacomb/Main.scala      | 17 -----
 .../scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala    | 78 +++-------------------
 2 files changed, 11 insertions(+), 84 deletions(-)

diff --git a/src/main/scala/uk/ac/ox/cs/rsacomb/Main.scala b/src/main/scala/uk/ac/ox/cs/rsacomb/Main.scala
index 1aa748a..7eb39e8 100644
--- a/src/main/scala/uk/ac/ox/cs/rsacomb/Main.scala
+++ b/src/main/scala/uk/ac/ox/cs/rsacomb/Main.scala
@@ -59,7 +59,6 @@ object RSAComb extends App {
       )
 
     val answers = rsa ask queries
-    Logger print s"Number of answers: ${answers.length}"
 
     /* Write answers to output file */
     os.write(
@@ -70,21 +69,5 @@ object RSAComb extends App {
 
     /* Generate simulation script */
     Logger.generateSimulationScripts(data, queries)
-
-    // Logger.print(s"$answers", Logger.VERBOSE)
-    // Logger print s"Number of answers: ${answers.length} (${answers.lengthWithMultiplicity})"
-    // Retrieve unfiltered answers
-    // val unfiltered = rsa.queryDataStore(
-    //   """
-    //     SELECT (count(?K) as ?COUNT)
-    //     WHERE {
-    //         ?K a rsa:QM .
-    //     }
-    //   """,
-    //   RSA.Prefixes
-    // )
-    // unfiltered.foreach((u) =>
-    //   Logger print s"Number of unfiltered answers: ${u.head._2}"
-    // )
   }
 }
diff --git a/src/main/scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala b/src/main/scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala
index a0d567e..f67eca9 100644
--- a/src/main/scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala
+++ b/src/main/scala/uk/ac/ox/cs/rsacomb/RSAOntology.scala
@@ -635,9 +635,14 @@ class RSAOntology(
     Logger.write(canonicalModel.rules.mkString("\n"), "canonical_model.dlog")
     RDFoxUtil.addRules(data, this.canonicalModel.rules)
 
+    /* Finalise canonical model */
+    data.clearRulesAxiomsExplicateFacts()
+
     RDFoxUtil.closeConnection(server, data)
 
     (query => {
+      Logger print s"Query ID: ${query.id}"
+
       val (server, data) = RDFoxUtil.openConnection(RSAOntology.DataStore)
 
       val filter = RSAOntology.filteringProgram(query)
@@ -650,85 +655,24 @@ class RSAOntology(
       )
       RDFoxUtil.addRules(data, filter.rules)
 
-      // TODO: We remove the rules, should we drop the tuple table as well?
-      //data.clearRulesAxiomsExplicateFacts()
-
       /* Gather answers to the query */
       val answers = RDFoxUtil
         .submitQuery(data, filter.answerQuery, RSA.Prefixes)
         .map(new ConjunctiveQueryAnswers(query, query.variables, _))
         .get
 
+      /* Drop filtering named graph to avoid running out of memory */
+      data.clearRulesAxiomsExplicateFacts()
+      data.deleteTupleTable(filter.target.getIRI)
+
       RDFoxUtil.closeConnection(server, data)
 
+      Logger print s"Number of answers: ${answers.length}"
+
       answers
     })
   }
 
-  //def ask(query: ConjunctiveQuery): ConjunctiveQueryAnswers = Logger.timed(
-  //  {
-  //    val (server, data) = RDFoxUtil.openConnection(RSAOntology.DataStore)
-  //    val canon = this.canonicalModel
-  //    val filter = RSAOntology.filteringProgram(query)
-
-  //    /* Upload data from data file */
-  //    RDFoxUtil.addData(data, datafiles: _*)
-
-  //    RDFoxUtil printStatisticsFor data
-
-  //    /* Top / equality axiomatization */
-  //    RDFoxUtil.addRules(data, topAxioms ++ equalityAxioms)
-
-  //    /* Generate `named` predicates */
-  //    RDFoxUtil.addFacts(data, (individuals ++ literals) map RSA.Named)
-  //    data.evaluateUpdate(
-  //      null, // the base IRI for the query (if null, a default is used)
-  //      RSA.Prefixes,
-  //      "INSERT { ?X a  rsa:Named } WHERE { ?X a owl:Thing }",
-  //      new java.util.HashMap[String, String]
-  //    )
-
-  //    /* Add canonical model */
-  //    Logger print s"Canonical model rules: ${canon.rules.length}"
-  //    RDFoxUtil.addRules(data, canon.rules)
-
-  //    Logger print s"Canonical model facts: ${canon.facts.length}"
-  //    RDFoxUtil.addFacts(data, canon.facts)
-
-  //    RDFoxUtil printStatisticsFor data
-
-  //    //{
-  //    //  import java.io.{PrintStream, FileOutputStream, File}
-  //    //  val rules1 = new FileOutputStream(new File("rules1-lubm200.dlog"))
-  //    //  val facts1 = new FileOutputStream(new File("facts1-lubm200.ttl"))
-  //    //  RDFoxUtil.export(data, rules1, facts1)
-  //    //  val rules2 = new PrintStream(new File("rules2-q34.dlog"))
-  //    //  rules2.print(filter.rules.mkString("\n"))
-  //    //}
-
-  //    /* Add filtering program */
-  //    Logger print s"Filtering program rules: ${filter.rules.length}"
-  //    RDFoxUtil.addRules(data, filter.rules)
-
-  //    RDFoxUtil printStatisticsFor data
-
-  //    /* Gather answers to the query */
-  //    val answers = {
-  //      val ans = filter.answerQuery
-  //      RDFoxUtil
-  //        .submitQuery(data, ans, RSA.Prefixes)
-  //        .map(new ConjunctiveQueryAnswers(query, query.variables, _))
-  //        .get
-  //    }
-
-  //    RDFoxUtil.closeConnection(server, data)
-
-  //    answers
-  //  },
-  //  "Answers computation",
-  //  Logger.DEBUG
-  //)
-
   /** Query the RDFox data store used for query answering.
     *
     * @note This method does not add any facts or rules to the data
-- 
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