diff --git a/arangod/RocksDBEngine/RocksDBCollection.cpp b/arangod/RocksDBEngine/RocksDBCollection.cpp
index 6d359316ef..e7fa8191d3 100644
--- a/arangod/RocksDBEngine/RocksDBCollection.cpp
+++ b/arangod/RocksDBEngine/RocksDBCollection.cpp
@@ -1176,7 +1176,7 @@ RocksDBOperationResult RocksDBCollection::removeDocument(
 /// @brief looks up a document by key, low level worker
 /// the key must be a string slice, no revision check is performed
 RocksDBOperationResult RocksDBCollection::lookupDocument(
-    transaction::Methods* trx, VPackSlice key, ManagedDocumentResult& mdr) {
+    transaction::Methods* trx, VPackSlice key, ManagedDocumentResult& mdr) const {
   RocksDBOperationResult res;
   if (!key.isString()) {
     res.reset(TRI_ERROR_ARANGO_DOCUMENT_KEY_BAD);
@@ -1228,7 +1228,7 @@ Result RocksDBCollection::lookupDocumentToken(transaction::Methods* trx,
 
 arangodb::Result RocksDBCollection::lookupRevisionVPack(
     TRI_voc_rid_t revisionId, transaction::Methods* trx,
-    arangodb::ManagedDocumentResult& mdr) {
+    arangodb::ManagedDocumentResult& mdr) const {
   TRI_ASSERT(trx->state()->isRunning());
   TRI_ASSERT(_objectId != 0);
 
diff --git a/arangod/RocksDBEngine/RocksDBCollection.h b/arangod/RocksDBEngine/RocksDBCollection.h
index dfc759cdf3..7d98bfb479 100644
--- a/arangod/RocksDBEngine/RocksDBCollection.h
+++ b/arangod/RocksDBEngine/RocksDBCollection.h
@@ -212,7 +212,7 @@ class RocksDBCollection final : public PhysicalCollection {
 
   arangodb::RocksDBOperationResult lookupDocument(
       transaction::Methods* trx, arangodb::velocypack::Slice key,
-      ManagedDocumentResult& result);
+      ManagedDocumentResult& result) const;
 
   arangodb::RocksDBOperationResult updateDocument(
       transaction::Methods* trx, TRI_voc_rid_t oldRevisionId,
@@ -220,7 +220,7 @@ class RocksDBCollection final : public PhysicalCollection {
       arangodb::velocypack::Slice const& newDoc, bool& waitForSync);
 
   arangodb::Result lookupRevisionVPack(TRI_voc_rid_t, transaction::Methods*,
-                                       arangodb::ManagedDocumentResult&);
+                                       arangodb::ManagedDocumentResult&) const;
 
  private:
   uint64_t const _objectId;  // rocksdb-specific object id for collection
diff --git a/arangod/RocksDBEngine/RocksDBIndex.h b/arangod/RocksDBEngine/RocksDBIndex.h
index 965a1e44f7..f740413a2b 100644
--- a/arangod/RocksDBEngine/RocksDBIndex.h
+++ b/arangod/RocksDBEngine/RocksDBIndex.h
@@ -81,7 +81,7 @@ class RocksDBIndex : public Index {
   RocksDBComparator* _cmp;
 
   cache::Manager* _cacheManager;
-  std::shared_ptr<cache::Cache> _cache;
+  mutable std::shared_ptr<cache::Cache> _cache;
   bool _useCache;
 };
 }
diff --git a/arangod/RocksDBEngine/RocksDBPrimaryIndex.cpp b/arangod/RocksDBEngine/RocksDBPrimaryIndex.cpp
index 8a15ac2b64..b21508d527 100644
--- a/arangod/RocksDBEngine/RocksDBPrimaryIndex.cpp
+++ b/arangod/RocksDBEngine/RocksDBPrimaryIndex.cpp
@@ -306,7 +306,7 @@ void RocksDBPrimaryIndex::toVelocyPackFigures(VPackBuilder& builder) const {
 }
 
 RocksDBToken RocksDBPrimaryIndex::lookupKey(transaction::Methods* trx,
-                                            arangodb::StringRef keyRef) {
+                                            arangodb::StringRef keyRef) const {
   auto key = RocksDBKey::PrimaryIndexValue(_objectId, keyRef);
   auto value = RocksDBValue::Empty(RocksDBEntryType::PrimaryIndexValue);
 
@@ -358,7 +358,7 @@ RocksDBToken RocksDBPrimaryIndex::lookupKey(transaction::Methods* trx,
 // TODO: remove this method?
 RocksDBToken RocksDBPrimaryIndex::lookupKey(transaction::Methods* trx,
                                             VPackSlice slice,
-                                            ManagedDocumentResult& result) {
+                                            ManagedDocumentResult& result) const {
   return lookupKey(trx, StringRef(slice));
 }
 
@@ -544,9 +544,9 @@ IndexIterator* RocksDBPrimaryIndex::anyIterator(
   return new RocksDBAnyIndexIterator(_collection, trx, mmdr, this);
 }
 
-void RocksDBPrimaryIndex::invokeOnAllElements(
+void RocksDBPrimaryIndex::invokeOnAllElements (
     transaction::Methods* trx,
-    std::function<bool(DocumentIdentifierToken const&)> callback) {
+    std::function<bool(DocumentIdentifierToken const&)> callback) const {
   ManagedDocumentResult mmdr;
   std::unique_ptr<IndexIterator> cursor(allIterator(trx, &mmdr, false));
   bool cnt = true;
diff --git a/arangod/RocksDBEngine/RocksDBPrimaryIndex.h b/arangod/RocksDBEngine/RocksDBPrimaryIndex.h
index cd33342e55..0e08b76e9c 100644
--- a/arangod/RocksDBEngine/RocksDBPrimaryIndex.h
+++ b/arangod/RocksDBEngine/RocksDBPrimaryIndex.h
@@ -160,10 +160,11 @@ class RocksDBPrimaryIndex final : public RocksDBIndex {
   void toVelocyPack(VPackBuilder&, bool, bool) const override;
   void toVelocyPackFigures(VPackBuilder&) const override;
 
-  RocksDBToken lookupKey(transaction::Methods* trx, arangodb::StringRef key);
+  RocksDBToken lookupKey(transaction::Methods* trx,
+                         arangodb::StringRef key) const;
   RocksDBToken lookupKey(transaction::Methods* trx,
                          arangodb::velocypack::Slice key,
-                         ManagedDocumentResult& result);
+                         ManagedDocumentResult& result) const;
 
   int insert(transaction::Methods*, TRI_voc_rid_t,
              arangodb::velocypack::Slice const&, bool isRollback) override;
@@ -196,7 +197,7 @@ class RocksDBPrimaryIndex final : public RocksDBIndex {
 
   void invokeOnAllElements(
       transaction::Methods* trx,
-      std::function<bool(DocumentIdentifierToken const&)> callback);
+      std::function<bool(DocumentIdentifierToken const&)> callback) const;
 
  private:
   /// @brief create the iterator, for a single attribute, IN operator