SERVER-67471 Improve RecordId usage performance

25 files changed, 52 insertions, 52 deletions

diff --git a/src/mongo/db/index/2d_access_method.cpp b/src/mongo/db/index/2d_access_method.cpp
index d81a9f6ea30..d5af3a86a97 100644
--- a/src/mongo/db/index/2d_access_method.cpp
+++ b/src/mongo/db/index/2d_access_method.cpp
@@ -64,7 +64,7 @@ void TwoDAccessMethod::doGetKeys(OperationContext* opCtx,
                                  KeyStringSet* keys,
                                  KeyStringSet* multikeyMetadataKeys,
                                  MultikeyPaths* multikeyPaths,
-                                 boost::optional<RecordId> id) const {
+                                 const boost::optional<RecordId>& id) const {
     ExpressionKeysPrivate::get2DKeys(pooledBufferBuilder,
                                      obj,
                                      _params,
diff --git a/src/mongo/db/index/2d_access_method.h b/src/mongo/db/index/2d_access_method.h
index e9621fcc7a2..a7ae364b994 100644
--- a/src/mongo/db/index/2d_access_method.h
+++ b/src/mongo/db/index/2d_access_method.h
@@ -70,7 +70,7 @@ private:
                    KeyStringSet* keys,
                    KeyStringSet* multikeyMetadataKeys,
                    MultikeyPaths* multikeyPaths,
-                   boost::optional<RecordId> id) const final;
+                   const boost::optional<RecordId>& id) const final;
 
     TwoDIndexingParams _params;
 };
diff --git a/src/mongo/db/index/btree_access_method.cpp b/src/mongo/db/index/btree_access_method.cpp
index 177f03ad34b..71c9bf86fec 100644
--- a/src/mongo/db/index/btree_access_method.cpp
+++ b/src/mongo/db/index/btree_access_method.cpp
@@ -79,7 +79,7 @@ void BtreeAccessMethod::doGetKeys(OperationContext* opCtx,
                                   KeyStringSet* keys,
                                   KeyStringSet* multikeyMetadataKeys,
                                   MultikeyPaths* multikeyPaths,
-                                  boost::optional<RecordId> id) const {
+                                  const boost::optional<RecordId>& id) const {
     const auto skipMultikey = context == GetKeysContext::kValidatingKeys &&
         !_descriptor->getEntry()->isMultikey(opCtx, collection);
     _keyGenerator->getKeys(pooledBufferBuilder,
diff --git a/src/mongo/db/index/btree_access_method.h b/src/mongo/db/index/btree_access_method.h
index 8f0e6304d20..5621c99933f 100644
--- a/src/mongo/db/index/btree_access_method.h
+++ b/src/mongo/db/index/btree_access_method.h
@@ -60,7 +60,7 @@ private:
                    KeyStringSet* keys,
                    KeyStringSet* multikeyMetadataKeys,
                    MultikeyPaths* multikeyPaths,
-                   boost::optional<RecordId> id) const final;
+                   const boost::optional<RecordId>& id) const final;
 
     // Our keys differ for V0 and V1.
     std::unique_ptr<BtreeKeyGenerator> _keyGenerator;
diff --git a/src/mongo/db/index/btree_key_generator.cpp b/src/mongo/db/index/btree_key_generator.cpp
index f386a3aba87..b845aa2af1a 100644
--- a/src/mongo/db/index/btree_key_generator.cpp
+++ b/src/mongo/db/index/btree_key_generator.cpp
@@ -173,7 +173,7 @@ void BtreeKeyGenerator::_getKeysArrEltFixed(const std::vector<const char*>& fiel
                                             const std::vector<PositionalPathInfo>& positionalInfo,
                                             MultikeyPaths* multikeyPaths,
                                             const CollatorInterface* collator,
-                                            boost::optional<RecordId> id) const {
+                                            const boost::optional<RecordId>& id) const {
     // fieldNamesTemp and fixedTemp are passed in by the caller to be used as temporary data
     // structures as we need them to be mutable in the recursion. When they are stored outside we
     // can reuse their memory.
@@ -210,7 +210,7 @@ void BtreeKeyGenerator::getKeys(SharedBufferFragmentBuilder& pooledBufferBuilder
                                 KeyStringSet* keys,
                                 MultikeyPaths* multikeyPaths,
                                 const CollatorInterface* collator,
-                                boost::optional<RecordId> id) const {
+                                const boost::optional<RecordId>& id) const {
     if (_isIdIndex) {
         // we special case for speed
         BSONElement e = obj["_id"];
@@ -311,7 +311,7 @@ size_t BtreeKeyGenerator::PositionalPathInfo::getApproximateSize() const {
 void BtreeKeyGenerator::_getKeysWithoutArray(SharedBufferFragmentBuilder& pooledBufferBuilder,
                                              const BSONObj& obj,
                                              const CollatorInterface* collator,
-                                             boost::optional<RecordId> id,
+                                             const boost::optional<RecordId>& id,
                                              KeyStringSet* keys) const {
 
     KeyString::PooledBuilder keyString{pooledBufferBuilder, _keyStringVersion, _ordering};
@@ -351,7 +351,7 @@ void BtreeKeyGenerator::_getKeysWithArray(std::vector<const char*>* fieldNames,
                                           const std::vector<PositionalPathInfo>& positionalInfo,
                                           MultikeyPaths* multikeyPaths,
                                           const CollatorInterface* collator,
-                                          boost::optional<RecordId> id) const {
+                                          const boost::optional<RecordId>& id) const {
     BSONElement arrElt;
 
     // A set containing the position of any indexed fields in the key pattern that traverse through
diff --git a/src/mongo/db/index/btree_key_generator.h b/src/mongo/db/index/btree_key_generator.h
index 7287b68420d..36a5146f80c 100644
--- a/src/mongo/db/index/btree_key_generator.h
+++ b/src/mongo/db/index/btree_key_generator.h
@@ -84,7 +84,7 @@ public:
                  KeyStringSet* keys,
                  MultikeyPaths* multikeyPaths,
                  const CollatorInterface* collator = nullptr,
-                 boost::optional<RecordId> id = boost::none) const;
+                 const boost::optional<RecordId>& id = boost::none) const;
 
     size_t getApproximateSize() const;
 
@@ -157,7 +157,7 @@ private:
                            const std::vector<PositionalPathInfo>& positionalInfo,
                            MultikeyPaths* multikeyPaths,
                            const CollatorInterface* collator,
-                           boost::optional<RecordId> id) const;
+                           const boost::optional<RecordId>& id) const;
 
     /**
      * An optimized version of the key generation algorithm to be used when it is known that 'obj'
@@ -166,7 +166,7 @@ private:
     void _getKeysWithoutArray(SharedBufferFragmentBuilder& pooledBufferBuilder,
                               const BSONObj& obj,
                               const CollatorInterface* collator,
-                              boost::optional<RecordId> id,
+                              const boost::optional<RecordId>& id,
                               KeyStringSet* keys) const;
 
     /**
@@ -228,7 +228,7 @@ private:
                              const std::vector<PositionalPathInfo>& positionalInfo,
                              MultikeyPaths* multikeyPaths,
                              const CollatorInterface* collator,
-                             boost::optional<RecordId> id) const;
+                             const boost::optional<RecordId>& id) const;
 
     KeyString::Value _buildNullKeyString() const;
 
diff --git a/src/mongo/db/index/column_store_sorter.cpp b/src/mongo/db/index/column_store_sorter.cpp
index f708518a560..ef82ad9bf13 100644
--- a/src/mongo/db/index/column_store_sorter.cpp
+++ b/src/mongo/db/index/column_store_sorter.cpp
@@ -82,7 +82,7 @@ ColumnStoreSorter::ColumnStoreSorter(size_t maxMemoryUsageBytes,
       _maxMemoryUsageBytes(maxMemoryUsageBytes),
       _spillFile(std::make_shared<Sorter<Key, Value>::File>(pathForNewSpillFile(), _stats)) {}
 
-void ColumnStoreSorter::add(PathView path, RecordId recordId, CellView cellContents) {
+void ColumnStoreSorter::add(PathView path, const RecordId& recordId, CellView cellContents) {
     auto& cellListAtPath = _dataByPath[path];
     if (cellListAtPath.empty()) {
         // Track memory usage of this new path.
@@ -181,7 +181,7 @@ void ColumnStoreSorter::spill() {
             writer.writeChunk();
             currentChunkSize = 0;
         }
-        for (auto ridAndCell : cellVector) {
+        for (auto& ridAndCell : cellVector) {
             const auto& cell = ridAndCell.second;
             currentChunkSize += path.size() + ridAndCell.first.memUsage() + cell.size();
             writer.addAlreadySorted(Key{path, ridAndCell.first},
diff --git a/src/mongo/db/index/column_store_sorter.h b/src/mongo/db/index/column_store_sorter.h
index 833213b3646..56f203c5f64 100644
--- a/src/mongo/db/index/column_store_sorter.h
+++ b/src/mongo/db/index/column_store_sorter.h
@@ -54,7 +54,7 @@ class ColumnStoreSorter {
 public:
     ColumnStoreSorter(size_t maxMemoryUsageBytes, StringData dbName, SorterFileStats* stats);
 
-    void add(PathView path, RecordId recordId, CellView cellContents);
+    void add(PathView path, const RecordId& recordId, CellView cellContents);
 
     size_t numSpills() const {
         return _numSpills;
diff --git a/src/mongo/db/index/expression_keys_private.cpp b/src/mongo/db/index/expression_keys_private.cpp
index 0e8fb0d6208..5463cc9de8d 100644
--- a/src/mongo/db/index/expression_keys_private.cpp
+++ b/src/mongo/db/index/expression_keys_private.cpp
@@ -489,7 +489,7 @@ void ExpressionKeysPrivate::get2DKeys(SharedBufferFragmentBuilder& pooledBufferB
                                       KeyStringSet* keys,
                                       KeyString::Version keyStringVersion,
                                       Ordering ordering,
-                                      boost::optional<RecordId> id) {
+                                      const boost::optional<RecordId>& id) {
     BSONElementMultiSet bSet;
 
     // Get all the nested location fields, but don't return individual elements from
@@ -581,7 +581,7 @@ void ExpressionKeysPrivate::getFTSKeys(SharedBufferFragmentBuilder& pooledBuffer
                                        KeyStringSet* keys,
                                        KeyString::Version keyStringVersion,
                                        Ordering ordering,
-                                       boost::optional<RecordId> id) {
+                                       const boost::optional<RecordId>& id) {
     fts::FTSIndexFormat::getKeys(
         pooledBufferBuilder, ftsSpec, obj, keys, keyStringVersion, ordering, id);
 }
@@ -598,7 +598,7 @@ void ExpressionKeysPrivate::getHashKeys(SharedBufferFragmentBuilder& pooledBuffe
                                         KeyString::Version keyStringVersion,
                                         Ordering ordering,
                                         bool ignoreArraysAlongPath,
-                                        boost::optional<RecordId> id) {
+                                        const boost::optional<RecordId>& id) {
     static const BSONObj nullObj = BSON("" << BSONNULL);
     auto hasFieldValue = false;
     KeyString::PooledBuilder keyString(pooledBufferBuilder, keyStringVersion, ordering);
@@ -672,7 +672,7 @@ void ExpressionKeysPrivate::getS2Keys(SharedBufferFragmentBuilder& pooledBufferB
                                       KeyString::Version keyStringVersion,
                                       SortedDataIndexAccessMethod::GetKeysContext context,
                                       Ordering ordering,
-                                      boost::optional<RecordId> id) {
+                                      const boost::optional<RecordId>& id) {
     std::vector<KeyString::HeapBuilder> keysToAdd;
 
     // Does one of our documents have a geo field?
diff --git a/src/mongo/db/index/expression_keys_private.h b/src/mongo/db/index/expression_keys_private.h
index dae982831ef..c97d48913c9 100644
--- a/src/mongo/db/index/expression_keys_private.h
+++ b/src/mongo/db/index/expression_keys_private.h
@@ -76,7 +76,7 @@ public:
                           KeyStringSet* keys,
                           KeyString::Version keyStringVersion,
                           Ordering ordering,
-                          boost::optional<RecordId> id = boost::none);
+                          const boost::optional<RecordId>& id = boost::none);
 
     //
     // FTS
@@ -88,7 +88,7 @@ public:
                            KeyStringSet* keys,
                            KeyString::Version keyStringVersion,
                            Ordering ordering,
-                           boost::optional<RecordId> id = boost::none);
+                           const boost::optional<RecordId>& id = boost::none);
 
     //
     // Hash
@@ -108,7 +108,7 @@ public:
                             KeyString::Version keyStringVersion,
                             Ordering ordering,
                             bool ignoreArraysAlongPath,
-                            boost::optional<RecordId> id = boost::none);
+                            const boost::optional<RecordId>& id = boost::none);
 
     /**
      * Hashing function used by both getHashKeys and the cursors we create.
@@ -133,7 +133,7 @@ public:
                           KeyString::Version keyStringVersion,
                           SortedDataIndexAccessMethod::GetKeysContext context,
                           Ordering ordering,
-                          boost::optional<RecordId> id = boost::none);
+                          const boost::optional<RecordId>& id = boost::none);
 };
 
 }  // namespace mongo
diff --git a/src/mongo/db/index/fts_access_method.cpp b/src/mongo/db/index/fts_access_method.cpp
index 4fbda54dae9..78f2d68b21e 100644
--- a/src/mongo/db/index/fts_access_method.cpp
+++ b/src/mongo/db/index/fts_access_method.cpp
@@ -47,7 +47,7 @@ void FTSAccessMethod::doGetKeys(OperationContext* opCtx,
                                 KeyStringSet* keys,
                                 KeyStringSet* multikeyMetadataKeys,
                                 MultikeyPaths* multikeyPaths,
-                                boost::optional<RecordId> id) const {
+                                const boost::optional<RecordId>& id) const {
     ExpressionKeysPrivate::getFTSKeys(pooledBufferBuilder,
                                       obj,
                                       _ftsSpec,
diff --git a/src/mongo/db/index/fts_access_method.h b/src/mongo/db/index/fts_access_method.h
index a1343553916..966b959af6a 100644
--- a/src/mongo/db/index/fts_access_method.h
+++ b/src/mongo/db/index/fts_access_method.h
@@ -60,7 +60,7 @@ private:
                    KeyStringSet* keys,
                    KeyStringSet* multikeyMetadataKeys,
                    MultikeyPaths* multikeyPaths,
-                   boost::optional<RecordId> id) const final;
+                   const boost::optional<RecordId>& id) const final;
 
     fts::FTSSpec _ftsSpec;
 };
diff --git a/src/mongo/db/index/hash_access_method.cpp b/src/mongo/db/index/hash_access_method.cpp
index ec7b05b3665..7e7e7862fd3 100644
--- a/src/mongo/db/index/hash_access_method.cpp
+++ b/src/mongo/db/index/hash_access_method.cpp
@@ -63,7 +63,7 @@ void HashAccessMethod::doGetKeys(OperationContext* opCtx,
                                  KeyStringSet* keys,
                                  KeyStringSet* multikeyMetadataKeys,
                                  MultikeyPaths* multikeyPaths,
-                                 boost::optional<RecordId> id) const {
+                                 const boost::optional<RecordId>& id) const {
     ExpressionKeysPrivate::getHashKeys(pooledBufferBuilder,
                                        obj,
                                        _keyPattern,
diff --git a/src/mongo/db/index/hash_access_method.h b/src/mongo/db/index/hash_access_method.h
index 851c841dbe2..6dc7df9e48d 100644
--- a/src/mongo/db/index/hash_access_method.h
+++ b/src/mongo/db/index/hash_access_method.h
@@ -67,7 +67,7 @@ private:
                    KeyStringSet* keys,
                    KeyStringSet* multikeyMetadataKeys,
                    MultikeyPaths* multikeyPaths,
-                   boost::optional<RecordId> id) const final;
+                   const boost::optional<RecordId>& id) const final;
 
     BSONObj _keyPattern;
 
diff --git a/src/mongo/db/index/index_access_method.cpp b/src/mongo/db/index/index_access_method.cpp
index 0144e00d973..f9cd8f7c7c2 100644
--- a/src/mongo/db/index/index_access_method.cpp
+++ b/src/mongo/db/index/index_access_method.cpp
@@ -437,7 +437,7 @@ RecordId SortedDataIndexAccessMethod::findSingle(OperationContext* opCtx,
 
     if (auto loc = _newInterface->findLoc(opCtx, actualKey)) {
         dassert(!loc->isNull());
-        return *loc;
+        return std::move(*loc);
     }
 
     return RecordId();
@@ -771,7 +771,7 @@ Status SortedDataIndexAccessMethod::BulkBuilderImpl::insert(
                       &_multikeyMetadataKeys,
                       multikeyPaths.get(),
                       loc,
-                      [&](Status status, const BSONObj&, boost::optional<RecordId>) {
+                      [&](Status status, const BSONObj&, const boost::optional<RecordId>&) {
                           // If a key generation error was suppressed, record the document as
                           // "skipped" so the index builder can retry at a point when data is
                           // consistent.
@@ -1018,7 +1018,7 @@ void SortedDataIndexAccessMethod::getKeys(OperationContext* opCtx,
                                           KeyStringSet* keys,
                                           KeyStringSet* multikeyMetadataKeys,
                                           MultikeyPaths* multikeyPaths,
-                                          boost::optional<RecordId> id,
+                                          const boost::optional<RecordId>& id,
                                           OnSuppressedErrorFn&& onSuppressedError) const {
     invariant(!id || _newInterface->rsKeyFormat() != KeyFormat::String || id->isStr(),
               fmt::format("RecordId is not in the same string format as its RecordStore; id: {}",
diff --git a/src/mongo/db/index/index_access_method.h b/src/mongo/db/index/index_access_method.h
index 7e3a4dd504a..5136faed942 100644
--- a/src/mongo/db/index/index_access_method.h
+++ b/src/mongo/db/index/index_access_method.h
@@ -387,8 +387,8 @@ public:
      * If any key generation errors are encountered and suppressed due to the provided GetKeysMode,
      * 'onSuppressedErrorFn' is called.
      */
-    using OnSuppressedErrorFn =
-        std::function<void(Status status, const BSONObj& obj, boost::optional<RecordId> loc)>;
+    using OnSuppressedErrorFn = std::function<void(
+        Status status, const BSONObj& obj, const boost::optional<RecordId>& loc)>;
     void getKeys(OperationContext* opCtx,
                  const CollectionPtr& collection,
                  SharedBufferFragmentBuilder& pooledBufferBuilder,
@@ -398,7 +398,7 @@ public:
                  KeyStringSet* keys,
                  KeyStringSet* multikeyMetadataKeys,
                  MultikeyPaths* multikeyPaths,
-                 boost::optional<RecordId> id,
+                 const boost::optional<RecordId>& id,
                  OnSuppressedErrorFn&& onSuppressedError = nullptr) const;
 
     /**
@@ -585,7 +585,7 @@ protected:
                            KeyStringSet* keys,
                            KeyStringSet* multikeyMetadataKeys,
                            MultikeyPaths* multikeyPaths,
-                           boost::optional<RecordId> id) const = 0;
+                           const boost::optional<RecordId>& id) const = 0;
 
     const IndexCatalogEntry* const _indexCatalogEntry;  // owned by IndexCatalog
     const IndexDescriptor* const _descriptor;
diff --git a/src/mongo/db/index/index_build_interceptor.cpp b/src/mongo/db/index/index_build_interceptor.cpp
index df708587511..6061ea3b90f 100644
--- a/src/mongo/db/index/index_build_interceptor.cpp
+++ b/src/mongo/db/index/index_build_interceptor.cpp
@@ -177,7 +177,7 @@ Status IndexBuildInterceptor::drainWritesIntoIndex(OperationContext* opCtx,
         while (record) {
             opCtx->checkForInterrupt();
 
-            RecordId currentRecordId = record->id;
+            auto& currentRecordId = record->id;
             BSONObj unownedDoc = record->data.toBson();
 
             // Don't apply this record if the total batch size in bytes would be too large.
@@ -207,7 +207,7 @@ Status IndexBuildInterceptor::drainWritesIntoIndex(OperationContext* opCtx,
 
             // Save the record ids of the documents inserted into the index for deletion later.
             // We can't delete records while holding a positioned cursor.
-            recordsAddedToIndex.push_back(currentRecordId);
+            recordsAddedToIndex.emplace_back(std::move(currentRecordId));
 
             // Don't continue if the batch is full. Allow the transaction to commit.
             if (batchSize == kBatchMaxSize) {
diff --git a/src/mongo/db/index/s2_access_method.cpp b/src/mongo/db/index/s2_access_method.cpp
index a2ea40dd9b1..eaba79ce7eb 100644
--- a/src/mongo/db/index/s2_access_method.cpp
+++ b/src/mongo/db/index/s2_access_method.cpp
@@ -143,7 +143,7 @@ void S2AccessMethod::doGetKeys(OperationContext* opCtx,
                                KeyStringSet* keys,
                                KeyStringSet* multikeyMetadataKeys,
                                MultikeyPaths* multikeyPaths,
-                               boost::optional<RecordId> id) const {
+                               const boost::optional<RecordId>& id) const {
     ExpressionKeysPrivate::getS2Keys(pooledBufferBuilder,
                                      obj,
                                      _descriptor->keyPattern(),
diff --git a/src/mongo/db/index/s2_access_method.h b/src/mongo/db/index/s2_access_method.h
index c25a8b47ce1..38999d95379 100644
--- a/src/mongo/db/index/s2_access_method.h
+++ b/src/mongo/db/index/s2_access_method.h
@@ -76,7 +76,7 @@ private:
                    KeyStringSet* keys,
                    KeyStringSet* multikeyMetadataKeys,
                    MultikeyPaths* multikeyPaths,
-                   boost::optional<RecordId> id) const final;
+                   const boost::optional<RecordId>& id) const final;
 
     S2IndexingParams _params;
 
diff --git a/src/mongo/db/index/s2_bucket_access_method.cpp b/src/mongo/db/index/s2_bucket_access_method.cpp
index 0da4cdc6f63..b9e926a753b 100644
--- a/src/mongo/db/index/s2_bucket_access_method.cpp
+++ b/src/mongo/db/index/s2_bucket_access_method.cpp
@@ -125,7 +125,7 @@ void S2BucketAccessMethod::doGetKeys(OperationContext* opCtx,
                                      KeyStringSet* keys,
                                      KeyStringSet* multikeyMetadataKeys,
                                      MultikeyPaths* multikeyPaths,
-                                     boost::optional<RecordId> id) const {
+                                     const boost::optional<RecordId>& id) const {
     ExpressionKeysPrivate::getS2Keys(pooledBufferBuilder,
                                      obj,
                                      _descriptor->keyPattern(),
diff --git a/src/mongo/db/index/s2_bucket_access_method.h b/src/mongo/db/index/s2_bucket_access_method.h
index 8996bfe78a5..c2d7186881d 100644
--- a/src/mongo/db/index/s2_bucket_access_method.h
+++ b/src/mongo/db/index/s2_bucket_access_method.h
@@ -76,7 +76,7 @@ private:
                    KeyStringSet* keys,
                    KeyStringSet* multikeyMetadataKeys,
                    MultikeyPaths* multikeyPaths,
-                   boost::optional<RecordId> id) const final;
+                   const boost::optional<RecordId>& id) const final;
 
     S2IndexingParams _params;
 
diff --git a/src/mongo/db/index/wildcard_access_method.cpp b/src/mongo/db/index/wildcard_access_method.cpp
index 4ea3cfc261c..0631158e40d 100644
--- a/src/mongo/db/index/wildcard_access_method.cpp
+++ b/src/mongo/db/index/wildcard_access_method.cpp
@@ -69,7 +69,7 @@ void WildcardAccessMethod::doGetKeys(OperationContext* opCtx,
                                      KeyStringSet* keys,
                                      KeyStringSet* multikeyMetadataKeys,
                                      MultikeyPaths* multikeyPaths,
-                                     boost::optional<RecordId> id) const {
+                                     const boost::optional<RecordId>& id) const {
     _keyGen.generateKeys(pooledBufferBuilder, obj, keys, multikeyMetadataKeys, id);
 }
 }  // namespace mongo
diff --git a/src/mongo/db/index/wildcard_access_method.h b/src/mongo/db/index/wildcard_access_method.h
index a82e7e616c2..1622941fb8e 100644
--- a/src/mongo/db/index/wildcard_access_method.h
+++ b/src/mongo/db/index/wildcard_access_method.h
@@ -75,7 +75,7 @@ private:
                    KeyStringSet* keys,
                    KeyStringSet* multikeyMetadataKeys,
                    MultikeyPaths* multikeyPaths,
-                   boost::optional<RecordId> id) const final;
+                   const boost::optional<RecordId>& id) const final;
 
     const WildcardKeyGenerator _keyGen;
 };
diff --git a/src/mongo/db/index/wildcard_key_generator.cpp b/src/mongo/db/index/wildcard_key_generator.cpp
index 6aa2aa64d7b..c04ba500eb7 100644
--- a/src/mongo/db/index/wildcard_key_generator.cpp
+++ b/src/mongo/db/index/wildcard_key_generator.cpp
@@ -114,7 +114,7 @@ void WildcardKeyGenerator::generateKeys(SharedBufferFragmentBuilder& pooledBuffe
                                         BSONObj inputDoc,
                                         KeyStringSet* keys,
                                         KeyStringSet* multikeyPaths,
-                                        boost::optional<RecordId> id) const {
+                                        const boost::optional<RecordId>& id) const {
     FieldRef rootPath;
     auto keysSequence = keys->extract_sequence();
     // multikeyPaths is allowed to be nullptr
@@ -139,7 +139,7 @@ void WildcardKeyGenerator::_traverseWildcard(SharedBufferFragmentBuilder& pooled
                                              FieldRef* path,
                                              KeyStringSet::sequence_type* keys,
                                              KeyStringSet::sequence_type* multikeyPaths,
-                                             boost::optional<RecordId> id) const {
+                                             const boost::optional<RecordId>& id) const {
     for (const auto& elem : obj) {
         // If the element's fieldName contains a ".", fast-path skip it because it's not queryable.
         if (elem.fieldNameStringData().find('.', 0) != std::string::npos)
@@ -185,7 +185,7 @@ bool WildcardKeyGenerator::_addKeyForNestedArray(SharedBufferFragmentBuilder& po
                                                  const FieldRef& fullPath,
                                                  bool enclosingObjIsArray,
                                                  KeyStringSet::sequence_type* keys,
-                                                 boost::optional<RecordId> id) const {
+                                                 const boost::optional<RecordId>& id) const {
     // If this element is an array whose parent is also an array, index it as a value.
     if (enclosingObjIsArray && elem.type() == BSONType::Array) {
         _addKey(pooledBufferBuilder, elem, fullPath, keys, id);
@@ -198,7 +198,7 @@ bool WildcardKeyGenerator::_addKeyForEmptyLeaf(SharedBufferFragmentBuilder& pool
                                                BSONElement elem,
                                                const FieldRef& fullPath,
                                                KeyStringSet::sequence_type* keys,
-                                               boost::optional<RecordId> id) const {
+                                               const boost::optional<RecordId>& id) const {
     invariant(elem.isABSONObj());
     if (elem.embeddedObject().isEmpty()) {
         // In keeping with the behaviour of regular indexes, an empty object is indexed as-is while
@@ -217,7 +217,7 @@ void WildcardKeyGenerator::_addKey(SharedBufferFragmentBuilder& pooledBufferBuil
                                    BSONElement elem,
                                    const FieldRef& fullPath,
                                    KeyStringSet::sequence_type* keys,
-                                   boost::optional<RecordId> id) const {
+                                   const boost::optional<RecordId>& id) const {
     // Wildcard keys are of the form { "": "path.to.field", "": <collation-aware value> }.
     KeyString::PooledBuilder keyString(pooledBufferBuilder, _keyStringVersion, _ordering);
     keyString.appendString(fullPath.dottedField());
diff --git a/src/mongo/db/index/wildcard_key_generator.h b/src/mongo/db/index/wildcard_key_generator.h
index 085fd191f37..4164fa9aa92 100644
--- a/src/mongo/db/index/wildcard_key_generator.h
+++ b/src/mongo/db/index/wildcard_key_generator.h
@@ -79,7 +79,7 @@ public:
                       BSONObj inputDoc,
                       KeyStringSet* keys,
                       KeyStringSet* multikeyPaths,
-                      boost::optional<RecordId> id = boost::none) const;
+                      const boost::optional<RecordId>& id = boost::none) const;
 
 private:
     // Traverses every path of the post-projection document, adding keys to the set as it goes.
@@ -89,7 +89,7 @@ private:
                            FieldRef* path,
                            KeyStringSet::sequence_type* keys,
                            KeyStringSet::sequence_type* multikeyPaths,
-                           boost::optional<RecordId> id) const;
+                           const boost::optional<RecordId>& id) const;
 
     // Helper functions to format the entry appropriately before adding it to the key/path tracker.
     void _addMultiKey(SharedBufferFragmentBuilder& pooledBufferBuilder,
@@ -99,7 +99,7 @@ private:
                  BSONElement elem,
                  const FieldRef& fullPath,
                  KeyStringSet::sequence_type* keys,
-                 boost::optional<RecordId> id) const;
+                 const boost::optional<RecordId>& id) const;
 
     // Helper to check whether the element is a nested array, and conditionally add it to 'keys'.
     bool _addKeyForNestedArray(SharedBufferFragmentBuilder& pooledBufferBuilder,
@@ -107,12 +107,12 @@ private:
                                const FieldRef& fullPath,
                                bool enclosingObjIsArray,
                                KeyStringSet::sequence_type* keys,
-                               boost::optional<RecordId> id) const;
+                               const boost::optional<RecordId>& id) const;
     bool _addKeyForEmptyLeaf(SharedBufferFragmentBuilder& pooledBufferBuilder,
                              BSONElement elem,
                              const FieldRef& fullPath,
                              KeyStringSet::sequence_type* keys,
-                             boost::optional<RecordId> id) const;
+                             const boost::optional<RecordId>& id) const;
 
     WildcardProjection _proj;
     const CollatorInterface* _collator;