SERVER-35921 Make IXSCAN use the proper MinKey/MaxKey bounds on LT and GT

7 files changed, 29 insertions, 16 deletions

diff --git a/jstests/core/index_bounds_maxkey.js b/jstests/core/index_bounds_maxkey.js
index f7cd1eb2e66..c581375e616 100644
--- a/jstests/core/index_bounds_maxkey.js
+++ b/jstests/core/index_bounds_maxkey.js
@@ -18,7 +18,7 @@ const proj = {
 };
 assertCoveredQueryAndCount({collection: coll, query: {a: {$gt: MaxKey}}, project: proj, count: 0});
 assertCoveredQueryAndCount({collection: coll, query: {a: {$gte: MaxKey}}, project: proj, count: 1});
-assertCoveredQueryAndCount({collection: coll, query: {a: {$lt: MaxKey}}, project: proj, count: 1});
+assertCoveredQueryAndCount({collection: coll, query: {a: {$lt: MaxKey}}, project: proj, count: 0});
 assertCoveredQueryAndCount({collection: coll, query: {a: {$lte: MaxKey}}, project: proj, count: 1});
 
 // Test that all documents are considered less than MaxKey, regardless of the presence of
diff --git a/jstests/core/index_bounds_minkey.js b/jstests/core/index_bounds_minkey.js
index 31d38a2115e..b1d244db0b7 100644
--- a/jstests/core/index_bounds_minkey.js
+++ b/jstests/core/index_bounds_minkey.js
@@ -16,7 +16,7 @@ const proj = {
     a: 1,
     _id: 0
 };
-assertCoveredQueryAndCount({collection: coll, query: {a: {$gt: MinKey}}, project: proj, count: 1});
+assertCoveredQueryAndCount({collection: coll, query: {a: {$gt: MinKey}}, project: proj, count: 0});
 assertCoveredQueryAndCount({collection: coll, query: {a: {$gte: MinKey}}, project: proj, count: 1});
 assertCoveredQueryAndCount({collection: coll, query: {a: {$lt: MinKey}}, project: proj, count: 0});
 assertCoveredQueryAndCount({collection: coll, query: {a: {$lte: MinKey}}, project: proj, count: 1});
diff --git a/jstests/core/min_max_key.js b/jstests/core/min_max_key.js
index e14a7ba4fda..5314e8d3436 100644
--- a/jstests/core/min_max_key.js
+++ b/jstests/core/min_max_key.js
@@ -89,9 +89,6 @@ testQueriesWithMinOrMaxKey();
 testTypeBracketedQueries();
 
 assert.commandWorked(coll.createIndex({a: 1}));
-// TODO: SERVER-35921 The results of the queries above should not change based on the
-// presence of an index
-assert.commandWorked(coll.dropIndexes());
 
 testQueriesWithMinOrMaxKey();
 testTypeBracketedQueries();
diff --git a/src/mongo/db/query/index_bounds_builder.cpp b/src/mongo/db/query/index_bounds_builder.cpp
index 3afc1f82587..ac40e38f9d0 100644
--- a/src/mongo/db/query/index_bounds_builder.cpp
+++ b/src/mongo/db/query/index_bounds_builder.cpp
@@ -277,6 +277,13 @@ void IndexBoundsBuilder::allValuesForField(const BSONElement& elt, OrderedInterv
         makeRangeInterval(bob.obj(), BoundInclusion::kIncludeBothStartAndEndKeys));
 }
 
+Interval IndexBoundsBuilder::allValuesRespectingInclusion(BoundInclusion bi) {
+    BSONObjBuilder bob;
+    bob.appendMinKey("");
+    bob.appendMaxKey("");
+    return makeRangeInterval(bob.obj(), bi);
+}
+
 Interval IndexBoundsBuilder::allValues() {
     BSONObjBuilder bob;
     bob.appendMinKey("");
@@ -526,9 +533,10 @@ void IndexBoundsBuilder::_translatePredicate(const MatchExpression* expr,
         const LTMatchExpression* node = static_cast<const LTMatchExpression*>(expr);
         BSONElement dataElt = node->getData();
 
-        // Everything is <= MaxKey.
+        // Everything is < MaxKey, except for MaxKey.
         if (MaxKey == dataElt.type()) {
-            oilOut->intervals.push_back(allValues());
+            oilOut->intervals.push_back(allValuesRespectingInclusion(
+                IndexBounds::makeBoundInclusionFromBoundBools(true, false)));
             *tightnessOut =
                 index.collator ? IndexBoundsBuilder::INEXACT_FETCH : IndexBoundsBuilder::EXACT;
             return;
@@ -564,9 +572,10 @@ void IndexBoundsBuilder::_translatePredicate(const MatchExpression* expr,
         const GTMatchExpression* node = static_cast<const GTMatchExpression*>(expr);
         BSONElement dataElt = node->getData();
 
-        // Everything is > MinKey.
+        // Everything is > MinKey, except MinKey.
         if (MinKey == dataElt.type()) {
-            oilOut->intervals.push_back(allValues());
+            oilOut->intervals.push_back(allValuesRespectingInclusion(
+                IndexBounds::makeBoundInclusionFromBoundBools(false, true)));
             *tightnessOut =
                 index.collator ? IndexBoundsBuilder::INEXACT_FETCH : IndexBoundsBuilder::EXACT;
             return;
diff --git a/src/mongo/db/query/index_bounds_builder.h b/src/mongo/db/query/index_bounds_builder.h
index e5099bbb816..0453df842cb 100644
--- a/src/mongo/db/query/index_bounds_builder.h
+++ b/src/mongo/db/query/index_bounds_builder.h
@@ -165,6 +165,11 @@ public:
      */
     static Interval allValues();
 
+    /**
+     * Returns an Interval from minKey to maxKey, preserving the specified inclusion.
+     */
+    static Interval allValuesRespectingInclusion(BoundInclusion bi);
+
     static void translateRegex(const RegexMatchExpression* rme,
                                const IndexEntry& index,
                                OrderedIntervalList* oil,
diff --git a/src/mongo/db/query/index_bounds_builder_test.cpp b/src/mongo/db/query/index_bounds_builder_test.cpp
index c6aae09515f..c9ee85f24fa 100644
--- a/src/mongo/db/query/index_bounds_builder_test.cpp
+++ b/src/mongo/db/query/index_bounds_builder_test.cpp
@@ -451,9 +451,9 @@ TEST(IndexBoundsBuilderTest, TranslateLtMaxKey) {
     IndexBoundsBuilder::translate(expr.get(), elt, testIndex, &oil, &tightness);
     ASSERT_EQUALS(oil.name, "a");
     ASSERT_EQUALS(oil.intervals.size(), 1U);
-    ASSERT_EQUALS(oil.intervals[0].toString(), "[MinKey, MaxKey]");
+    ASSERT_EQUALS(oil.intervals[0].toString(), "[MinKey, MaxKey)");
     ASSERT_TRUE(oil.intervals[0].startInclusive);
-    ASSERT_TRUE(oil.intervals[0].endInclusive);
+    ASSERT_FALSE(oil.intervals[0].endInclusive);
     ASSERT_EQUALS(tightness, IndexBoundsBuilder::EXACT);
 }
 
@@ -595,8 +595,8 @@ TEST(IndexBoundsBuilderTest, TranslateGtMinKey) {
     IndexBoundsBuilder::translate(expr.get(), elt, testIndex, &oil, &tightness);
     ASSERT_EQUALS(oil.name, "a");
     ASSERT_EQUALS(oil.intervals.size(), 1U);
-    ASSERT_EQUALS(oil.intervals[0].toString(), "[MinKey, MaxKey]");
-    ASSERT_TRUE(oil.intervals[0].startInclusive);
+    ASSERT_EQUALS(oil.intervals[0].toString(), "(MinKey, MaxKey]");
+    ASSERT_FALSE(oil.intervals[0].startInclusive);
     ASSERT_TRUE(oil.intervals[0].endInclusive);
     ASSERT_EQUALS(tightness, IndexBoundsBuilder::EXACT);
 }
@@ -2770,7 +2770,8 @@ TEST(IndexBoundsBuilderTest, LTMaxKeyWithCollator) {
     ASSERT_EQUALS(oil.name, "a");
     ASSERT_EQUALS(oil.intervals.size(), 1U);
     ASSERT_EQUALS(Interval::INTERVAL_EQUALS,
-                  oil.intervals[0].compare(IndexBoundsBuilder::allValues()));
+                  oil.intervals[0].compare(IndexBoundsBuilder::allValuesRespectingInclusion(
+                      BoundInclusion::kIncludeStartKeyOnly)));
     ASSERT_EQUALS(tightness, IndexBoundsBuilder::INEXACT_FETCH);
 }
 
@@ -2810,7 +2811,8 @@ TEST(IndexBoundsBuilderTest, GTMinKeyWithCollator) {
     ASSERT_EQUALS(oil.name, "a");
     ASSERT_EQUALS(oil.intervals.size(), 1U);
     ASSERT_EQUALS(Interval::INTERVAL_EQUALS,
-                  oil.intervals[0].compare(IndexBoundsBuilder::allValues()));
+                  oil.intervals[0].compare(IndexBoundsBuilder::allValuesRespectingInclusion(
+                      BoundInclusion::kIncludeEndKeyOnly)));
     ASSERT_EQUALS(tightness, IndexBoundsBuilder::INEXACT_FETCH);
 }
 
diff --git a/src/mongo/db/query/query_planner_wildcard_index_test.cpp b/src/mongo/db/query/query_planner_wildcard_index_test.cpp
index eba458736af..ba901fd4577 100644
--- a/src/mongo/db/query/query_planner_wildcard_index_test.cpp
+++ b/src/mongo/db/query/query_planner_wildcard_index_test.cpp
@@ -381,7 +381,7 @@ TEST_F(QueryPlannerWildcardTest, RangeIndexScanMinKeyMaxKey) {
         "{fetch: {filter: null, node: "
         "{ixscan: {filter: null, pattern: {'$_path': 1, a: 1},"
         "bounds: {'$_path': [['a','a',true,true], ['a.', 'a/', true, false]], 'a': [['MinKey', "
-        "'MaxKey', true, true]]}}}}}");
+        "'MaxKey', false, false]]}}}}}");
 }
 
 TEST_F(QueryPlannerWildcardTest, RangeIndexScanNestedField) {