1 files changed, 23 insertions, 9 deletions

diff --git a/src/mongo/db/query/plan_cache.cpp b/src/mongo/db/query/plan_cache.cpp
index 23d939df000..77bc3fb0898 100644
--- a/src/mongo/db/query/plan_cache.cpp
+++ b/src/mongo/db/query/plan_cache.cpp
@@ -62,10 +62,6 @@ namespace {
 ServerStatusMetricField<Counter64> totalPlanCacheSizeEstimateBytesMetric(
     "query.planCacheTotalSizeEstimateBytes", &PlanCacheEntry::planCacheTotalSizeEstimateBytes);
 
-// Delimiters for cache key encoding.
-const char kEncodeDiscriminatorsBegin = '<';
-const char kEncodeDiscriminatorsEnd = '>';
-
 void encodeIndexabilityForDiscriminators(const MatchExpression* tree,
                                          const IndexToDiscriminatorMap& discriminators,
                                          StringBuilder* keyBuilder) {
@@ -74,12 +70,12 @@ void encodeIndexabilityForDiscriminators(const MatchExpression* tree,
     }
 }
 
-void encodeIndexability(const MatchExpression* tree,
-                        const PlanCacheIndexabilityState& indexabilityState,
-                        StringBuilder* keyBuilder) {
+void encodeIndexabilityRecursive(const MatchExpression* tree,
+                                 const PlanCacheIndexabilityState& indexabilityState,
+                                 StringBuilder* keyBuilder) {
     if (!tree->path().empty()) {
         const IndexToDiscriminatorMap& discriminators =
-            indexabilityState.getDiscriminators(tree->path());
+            indexabilityState.getPathDiscriminators(tree->path());
         IndexToDiscriminatorMap wildcardDiscriminators =
             indexabilityState.buildWildcardDiscriminators(tree->path());
         if (!discriminators.empty() || !wildcardDiscriminators.empty()) {
@@ -99,8 +95,26 @@ void encodeIndexability(const MatchExpression* tree,
     }
 
     for (size_t i = 0; i < tree->numChildren(); ++i) {
-        encodeIndexability(tree->getChild(i), indexabilityState, keyBuilder);
+        encodeIndexabilityRecursive(tree->getChild(i), indexabilityState, keyBuilder);
+    }
+}
+
+void encodeIndexability(const MatchExpression* tree,
+                        const PlanCacheIndexabilityState& indexabilityState,
+                        StringBuilder* keyBuilder) {
+    // Before encoding the indexability of the leaf MatchExpressions, apply the global
+    // discriminators to the expression as a whole. This is for cases such as partial indexes which
+    // must discriminate based on the entire query.
+    const auto& globalDiscriminators = indexabilityState.getGlobalDiscriminators();
+    if (!globalDiscriminators.empty()) {
+        *keyBuilder << kEncodeGlobalDiscriminatorsBegin;
+        for (auto&& indexAndDiscriminatorPair : globalDiscriminators) {
+            *keyBuilder << indexAndDiscriminatorPair.second.isMatchCompatibleWithIndex(tree);
+        }
+        *keyBuilder << kEncodeGlobalDiscriminatorsEnd;
     }
+
+    encodeIndexabilityRecursive(tree, indexabilityState, keyBuilder);
 }
 
 }  // namespace