From 77f4b410885918e6209ab577d032980eb9c09c7f Mon Sep 17 00:00:00 2001
From: Osma Suominen <osma.suominen@helsinki.fi>
Date: Tue, 1 Dec 2020 15:26:28 +0200
Subject: [PATCH] Use GRAPH, not FROM in alphabetical letters query - much
 faster on Fuseki

---
 model/sparql/GenericSparql.php | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/model/sparql/GenericSparql.php b/model/sparql/GenericSparql.php
index f47dceeae..d505ea772 100644
--- a/model/sparql/GenericSparql.php
+++ b/model/sparql/GenericSparql.php
@@ -1337,15 +1337,17 @@ public function queryConceptsAlphabetical($letter, $lang, $limit = null, $offset
      * @return string sparql query
      */
     private function generateFirstCharactersQuery($lang, $classes) {
-        $fcl = $this->generateFromClause();
+        $gcl = $this->graphClause;
         $classes = (isset($classes) && sizeof($classes) > 0) ? $classes : array('http://www.w3.org/2004/02/skos/core#Concept');
         $values = $this->formatValues('?type', $classes, 'uri');
         $query = <<<EOQ
-SELECT DISTINCT (ucase(str(substr(?label, 1, 1))) as ?l) $fcl WHERE {
-  ?c skos:prefLabel ?label .
-  ?c a ?type
-  FILTER(langMatches(lang(?label), '$lang'))
-  $values
+SELECT DISTINCT (ucase(str(substr(?label, 1, 1))) as ?l) WHERE {
+  $gcl {
+    ?c skos:prefLabel ?label .
+    ?c a ?type
+    FILTER(langMatches(lang(?label), '$lang'))
+    $values
+  }
 }
 EOQ;
         return $query;