From 76f84f2c6c7672d7d58173ac35b72b8d55e9d5c9 Mon Sep 17 00:00:00 2001
From: Jan <jsteemann@users.noreply.github.com>
Date: Tue, 26 Nov 2019 10:44:45 +0100
Subject: [PATCH] Allow the optimizer to use indexes (#10543)

* Allow the optimizer to use indexes

when a collection attribute is compared to anexpansion followed by an attribute name, e.g. `doc.value IN something[*].name`.

* Update CHANGELOG
---
 CHANGELOG                                    |  4 +++
 arangod/Indexes/Index.cpp                    |  3 +-
 tests/js/server/aql/aql-optimizer-indexes.js | 34 ++++++++++++++++++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 5fa8c29199..26b3ac0444 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,10 @@
 v3.5.3 (XXXX-XX-XX)
 -------------------
 
+* Allow the optimizer to use indexes when a collection attribute is compared to
+  an expansion followed by an attribute name, e.g.
+  `doc.value IN something[*].name`.
+
 * Updated arangosync to 0.7.0.
 
 * Fixed issue #10470: The WebUI now shows potential errors and details which
diff --git a/arangod/Indexes/Index.cpp b/arangod/Indexes/Index.cpp
index 2831d6431f..636755e804 100644
--- a/arangod/Indexes/Index.cpp
+++ b/arangod/Indexes/Index.cpp
@@ -825,8 +825,7 @@ bool Index::canUseConditionPart(arangodb::aql::AstNode const* access,
        other->type == arangodb::aql::NODE_TYPE_ATTRIBUTE_ACCESS)) {
     // value IN a.b  OR  value IN a.b[*]
     arangodb::aql::Ast::getReferencedVariables(access, variables);
-    if (other->type == arangodb::aql::NODE_TYPE_ATTRIBUTE_ACCESS &&
-        variables.find(reference) != variables.end()) {
+    if (variables.find(reference) != variables.end()) {
       variables.clear();
       arangodb::aql::Ast::getReferencedVariables(other, variables);
     }
diff --git a/tests/js/server/aql/aql-optimizer-indexes.js b/tests/js/server/aql/aql-optimizer-indexes.js
index 44c37fe706..eeed785ae5 100644
--- a/tests/js/server/aql/aql-optimizer-indexes.js
+++ b/tests/js/server/aql/aql-optimizer-indexes.js
@@ -56,6 +56,40 @@ function optimizerIndexesTestSuite () {
       db._drop("UnitTestsCollection");
     },
 
+    testIndexUsedForExpansion1 : function () {
+      let query = "LET test = NOOPT([{ value: 1 }, { value : 2 }]) FOR doc IN " + c.name() + " FILTER doc.value IN test[*].value SORT doc.value RETURN doc.value";
+
+      let plan = AQL_EXPLAIN(query).plan;
+      let nodeTypes = plan.nodes.map(function(node) {
+        return node.type;
+      });
+
+      assertEqual("SingletonNode", nodeTypes[0], query);
+      assertNotEqual(-1, nodeTypes.indexOf("IndexNode"), query);
+
+      let results = AQL_EXECUTE(query);
+      assertEqual([ 1, 2 ], results.json, query);
+      assertEqual(0, results.stats.scannedFull);
+      assertTrue(results.stats.scannedIndex > 0);
+    },
+    
+    testIndexUsedForExpansion2 : function () {
+      let query = "LET test = NOOPT([1, 2]) FOR doc IN " + c.name() + " FILTER doc.value IN test[*] SORT doc.value RETURN doc.value";
+
+      let plan = AQL_EXPLAIN(query).plan;
+      let nodeTypes = plan.nodes.map(function(node) {
+        return node.type;
+      });
+
+      assertEqual("SingletonNode", nodeTypes[0], query);
+      assertNotEqual(-1, nodeTypes.indexOf("IndexNode"), query);
+
+      let results = AQL_EXECUTE(query);
+      assertEqual([ 1, 2 ], results.json, query);
+      assertEqual(0, results.stats.scannedFull);
+      assertTrue(results.stats.scannedIndex > 0);
+    },
+
     testMultiIndexesOrCondition : function () {
       let values = [ 
         [ "abc", true, true ],