diff --git a/cql3/abstract_marker.cc b/cql3/abstract_marker.cc
index b217f80299..2a14ccbc60 100644
--- a/cql3/abstract_marker.cc
+++ b/cql3/abstract_marker.cc
@@ -31,7 +31,7 @@
 
 namespace cql3 {
 
-::shared_ptr<term> abstract_marker::raw::prepare(sstring keyspace, ::shared_ptr<column_specification> receiver)
+::shared_ptr<term> abstract_marker::raw::prepare(const sstring& keyspace, ::shared_ptr<column_specification> receiver)
 {
     auto receiver_type = ::dynamic_pointer_cast<db::marshal::collection_type>(receiver->type);
     if (receiver_type != nullptr) {
@@ -45,7 +45,7 @@ namespace cql3 {
     assert(0);
 }
 
-::shared_ptr<term> abstract_marker::in_raw::prepare(sstring keyspace, ::shared_ptr<column_specification> receiver) {
+::shared_ptr<term> abstract_marker::in_raw::prepare(const sstring& keyspace, ::shared_ptr<column_specification> receiver) {
     return ::make_shared<lists::marker>(_bind_index, make_in_receiver(receiver));
 }
 
diff --git a/cql3/abstract_marker.hh b/cql3/abstract_marker.hh
index 10e8548f1e..6b0da7e195 100644
--- a/cql3/abstract_marker.hh
+++ b/cql3/abstract_marker.hh
@@ -68,9 +68,9 @@ public:
             : _bind_index{bind_index}
         { }
 
-        virtual ::shared_ptr<term> prepare(sstring keyspace, ::shared_ptr<column_specification> receiver) override;
+        virtual ::shared_ptr<term> prepare(const sstring& keyspace, ::shared_ptr<column_specification> receiver) override;
 
-        virtual assignment_testable::test_result test_assignment(sstring keyspace, ::shared_ptr<column_specification> receiver) override {
+        virtual assignment_testable::test_result test_assignment(const sstring& keyspace, ::shared_ptr<column_specification> receiver) override {
             return assignment_testable::test_result::WEAKLY_ASSIGNABLE;
         }
 
@@ -97,7 +97,7 @@ public:
             return ::make_shared<column_specification>(receiver->ks_name, receiver->cf_name, in_name, db::marshal::list_type::get_instance(receiver->type, false));
         }
 
-        virtual ::shared_ptr<term> prepare(sstring keyspace, ::shared_ptr<column_specification> receiver) override;
+        virtual ::shared_ptr<term> prepare(const sstring& keyspace, ::shared_ptr<column_specification> receiver) override;
     };
 };
 
diff --git a/cql3/assignment_testable.hh b/cql3/assignment_testable.hh
index e2a92270f5..24a8b91d87 100644
--- a/cql3/assignment_testable.hh
+++ b/cql3/assignment_testable.hh
@@ -49,7 +49,7 @@ public:
 
     // Test all elements of toTest for assignment. If all are exact match, return exact match. If any is not assignable,
     // return not assignable. Otherwise, return weakly assignable.
-    static test_result test_all(sstring keyspace, ::shared_ptr<column_specification> receiver, const std::vector<::shared_ptr<assignment_testable>>& to_test) {
+    static test_result test_all(const sstring& keyspace, ::shared_ptr<column_specification> receiver, const std::vector<::shared_ptr<assignment_testable>>& to_test) {
         test_result res = test_result::EXACT_MATCH;
         for (auto&& rt : to_test) {
             if (rt == nullptr) {
@@ -77,7 +77,7 @@ public:
      * Most caller should just call the isAssignable() method on the result, though functions have a use for
      * testing "strong" equality to decide the most precise overload to pick when multiple could match.
      */
-    virtual test_result test_assignment(sstring keyspace, ::shared_ptr<column_specification> receiver) = 0;
+    virtual test_result test_assignment(const sstring& keyspace, ::shared_ptr<column_specification> receiver) = 0;
 };
 
 }
diff --git a/cql3/attributes.hh b/cql3/attributes.hh
index 3937c679ae..6ca42c0a1c 100644
--- a/cql3/attributes.hh
+++ b/cql3/attributes.hh
@@ -53,7 +53,7 @@ private:
     { }
 
 public:
-    bool uses_function(sstring ks_name, sstring function_name) const {
+    bool uses_function(const sstring& ks_name, const sstring& function_name) const {
         return (_timestamp && _timestamp.value()->uses_function(ks_name, function_name))
             || (_time_to_live && _time_to_live.value()->uses_function(ks_name, function_name));
     }
@@ -126,18 +126,18 @@ public:
         ::shared_ptr<term::raw> timestamp;
         ::shared_ptr<term::raw> time_to_live;
 
-        std::unique_ptr<attributes> prepare(sstring ks_name, sstring cf_name) {
+        std::unique_ptr<attributes> prepare(const sstring& ks_name, const sstring& cf_name) {
             auto ts = !timestamp ? ::shared_ptr<term>{} : timestamp->prepare(ks_name, timestamp_receiver(ks_name, cf_name));
             auto ttl = !time_to_live ? ::shared_ptr<term>{} : time_to_live->prepare(ks_name, time_to_live_receiver(ks_name, cf_name));
             return std::unique_ptr<attributes>{new attributes{std::move(ts), std::move(ttl)}};
         }
 
     private:
-        ::shared_ptr<column_specification> timestamp_receiver(const sstring ks_name, sstring cf_name) {
+        ::shared_ptr<column_specification> timestamp_receiver(const sstring& ks_name, const sstring& cf_name) {
             return ::make_shared<column_specification>(ks_name, cf_name, ::make_shared<column_identifier>("[timestamp]", true), data_type_for<int64_t>());
         }
 
-        ::shared_ptr<column_specification> time_to_live_receiver(sstring ks_name, sstring cf_name) {
+        ::shared_ptr<column_specification> time_to_live_receiver(const sstring& ks_name, const sstring& cf_name) {
             return ::make_shared<column_specification>(ks_name, cf_name, ::make_shared<column_identifier>("[ttl]", true), data_type_for<int32_t>());
         }
     };
diff --git a/cql3/column_condition.hh b/cql3/column_condition.hh
index e7a9ae4ef4..528126135a 100644
--- a/cql3/column_condition.hh
+++ b/cql3/column_condition.hh
@@ -106,7 +106,7 @@ public:
     }
 #endif
 
-    bool uses_function(sstring ks_name, sstring function_name) const {
+    bool uses_function(const sstring& ks_name, const sstring& function_name) const {
         throw std::runtime_error("not implemented");
 #if 0
         if (collectionElement != null && collectionElement.usesFunction(ksName, functionName))
diff --git a/cql3/constants.hh b/cql3/constants.hh
index 28b078bf8f..cd74644889 100644
--- a/cql3/constants.hh
+++ b/cql3/constants.hh
@@ -142,7 +142,7 @@ public:
             return ::make_shared<literal>(type::HEX, text);
         }
 
-        virtual ::shared_ptr<term> prepare(sstring keyspace, ::shared_ptr<column_specification> receiver) override {
+        virtual ::shared_ptr<term> prepare(const sstring& keyspace, ::shared_ptr<column_specification> receiver) override {
             throw std::runtime_error("not implemented");
 #if 0
             if (!testAssignment(keyspace, receiver).isAssignable())
@@ -177,7 +177,7 @@ public:
         }
 #endif
 
-        virtual assignment_testable::test_result test_assignment(sstring keyspace, ::shared_ptr<column_specification> receiver) override {
+        virtual assignment_testable::test_result test_assignment(const sstring& keyspace, ::shared_ptr<column_specification> receiver) override {
             throw new std::runtime_error("not implemented");
 #if 0
             CQL3Type receiverType = receiver.type.asCQL3Type();
diff --git a/cql3/cql_statement.hh b/cql3/cql_statement.hh
index 15c50d8cb4..8ddde8477e 100644
--- a/cql3/cql_statement.hh
+++ b/cql3/cql_statement.hh
@@ -72,7 +72,7 @@ public:
     virtual future<std::experimental::optional<transport::messages::result_message>>
         execute_internal(service::query_state& state, const query_options& options) = 0;
 
-    virtual bool uses_function(sstring ks_name, sstring function_name) const = 0;
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const = 0;
 };
 
 }
diff --git a/cql3/functions/abstract_function.hh b/cql3/functions/abstract_function.hh
index bafe066840..abc8677ffa 100644
--- a/cql3/functions/abstract_function.hh
+++ b/cql3/functions/abstract_function.hh
@@ -66,7 +66,7 @@ public:
             && _return_type == x._return_type;
     }
 
-    virtual bool uses_function(sstring ks_name, sstring function_name) override {
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) override {
         return _name.keyspace == ks_name && _name.name == function_name;
     }
 
diff --git a/cql3/functions/function.hh b/cql3/functions/function.hh
index 90f5189c32..6982be983b 100644
--- a/cql3/functions/function.hh
+++ b/cql3/functions/function.hh
@@ -64,7 +64,7 @@ public:
 
     virtual void print(std::ostream& os) const = 0;
 protected:
-    virtual bool uses_function(sstring ks_name, sstring function_name) = 0;
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) = 0;
     virtual bool has_reference_to(function& f) = 0;
     friend class function_call;
     friend std::ostream& operator<<(std::ostream& os, const function& f);
diff --git a/cql3/functions/function_call.hh b/cql3/functions/function_call.hh
index a7da7235c3..86e2ed9492 100644
--- a/cql3/functions/function_call.hh
+++ b/cql3/functions/function_call.hh
@@ -41,8 +41,8 @@ public:
             : _fun(std::move(fun)), _terms(std::move(terms)) {
     }
 
-    virtual bool uses_function(sstring ks_name, sstring function_name) const override {
-        return _fun->uses_function(std::move(ks_name), std::move(function_name));
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const override {
+        return _fun->uses_function(ks_name, function_name);
     }
 
     virtual void collect_marker_specification(shared_ptr<variable_specifications> bound_names) override {
diff --git a/cql3/operation.hh b/cql3/operation.hh
index f62bcbf558..cd0a21acc3 100644
--- a/cql3/operation.hh
+++ b/cql3/operation.hh
@@ -77,7 +77,7 @@ protected:
     { }
 
 public:
-    virtual bool uses_function(sstring ks_name, sstring function_name) const {
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const {
         return _t && _t->uses_function(ks_name, function_name);
     }
 
diff --git a/cql3/restrictions/restriction.hh b/cql3/restrictions/restriction.hh
index 038ef7fb60..f39707140d 100644
--- a/cql3/restrictions/restriction.hh
+++ b/cql3/restrictions/restriction.hh
@@ -56,7 +56,7 @@ public:
      * @param functionName the function name
      * @return <code>true</code> if one of the restrictions use the specified function, <code>false</code> otherwise.
      */
-    virtual bool uses_function(sstring ksName, sstring functionName) = 0;
+    virtual bool uses_function(const sstring& ksName, const sstring& functionName) = 0;
 
     /**
      * Checks if the specified bound is set or not.
diff --git a/cql3/statements/modification_statement.hh b/cql3/statements/modification_statement.hh
index 39e72fcc74..f4438e2aa8 100644
--- a/cql3/statements/modification_statement.hh
+++ b/cql3/statements/modification_statement.hh
@@ -128,7 +128,7 @@ public:
         , _column_operations{}
     { }
 
-    virtual bool uses_function(sstring ks_name, sstring function_name) const override {
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const override {
         if (attrs->uses_function(ks_name, function_name)) {
             return true;
         }
diff --git a/cql3/statements/parsed_statement.hh b/cql3/statements/parsed_statement.hh
index 7f791d79c4..43110db0b0 100644
--- a/cql3/statements/parsed_statement.hh
+++ b/cql3/statements/parsed_statement.hh
@@ -78,7 +78,7 @@ public:
 
     virtual std::unique_ptr<prepared> prepare(database& db) = 0;
 
-    virtual bool uses_function(sstring ks_name, sstring function_name) const {
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const {
         return false;
     }
 };
diff --git a/cql3/statements/use_statement.hh b/cql3/statements/use_statement.hh
index 4d842f8ff5..ae44205ccd 100644
--- a/cql3/statements/use_statement.hh
+++ b/cql3/statements/use_statement.hh
@@ -49,7 +49,7 @@ public:
         return std::make_unique<parsed_statement::prepared>(this->shared_from_this());
     }
 
-    virtual bool uses_function(sstring ks_name, sstring function_name) const override {
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const override {
         return parsed_statement::uses_function(ks_name, function_name);
     }
 
diff --git a/cql3/term.hh b/cql3/term.hh
index 111a21fd3c..04e0a6661f 100644
--- a/cql3/term.hh
+++ b/cql3/term.hh
@@ -83,7 +83,7 @@ public:
      */
     virtual bool contains_bind_marker() const = 0;
 
-    virtual bool uses_function(sstring ks_name, sstring function_name) const = 0;
+    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const = 0;
 
     /**
      * A parsed, non prepared (thus untyped) term.
@@ -106,14 +106,14 @@ public:
          * case this RawTerm describe a list index or a map key, etc...
          * @return the prepared term.
          */
-        virtual ::shared_ptr<term> prepare(sstring keyspace, ::shared_ptr<column_specification> receiver) = 0;
+        virtual ::shared_ptr<term> prepare(const sstring& keyspace, ::shared_ptr<column_specification> receiver) = 0;
 
         virtual sstring to_string() = 0;
     };
 
     class multi_column_raw : public virtual raw {
     public:
-        virtual ::shared_ptr<term> prepare(sstring keyspace, const std::vector<column_specification>& receiver) = 0;
+        virtual ::shared_ptr<term> prepare(const sstring& keyspace, const std::vector<column_specification>& receiver) = 0;
     };
 };
 
@@ -140,7 +140,7 @@ public:
             return this->shared_from_this();
         }
 
-        virtual bool uses_function(sstring ks_name, sstring function_name) const override {
+        virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const override {
             return false;
         }
 
@@ -183,7 +183,7 @@ public:
      */
     class non_terminal : public term {
     public:
-        virtual bool uses_function(sstring ks_name, sstring function_name) const override {
+        virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const override {
             return false;
         }