diff --git a/libraries/chain/account_object.cpp b/libraries/chain/account_object.cpp
index 90d97692a..c19eedb64 100644
--- a/libraries/chain/account_object.cpp
+++ b/libraries/chain/account_object.cpp
@@ -119,9 +119,9 @@ set<account_id_type> account_member_index::get_account_members(const account_obj
       result.insert(auth.first);
    return result;
 }
-set<public_key_type> account_member_index::get_key_members(const account_object& a)const
+set<public_key_type, account_member_index::key_compare> account_member_index::get_key_members(const account_object& a)const
 {
-   set<public_key_type> result;
+   set<public_key_type, key_compare> result;
    for( auto auth : a.owner.key_auths )
       result.insert(auth.first);
    for( auto auth : a.active.key_auths )
@@ -213,7 +213,7 @@ void account_member_index::object_modified(const object& after)
 
 
     {
-       set<public_key_type> after_key_members = get_key_members(a);
+       set<public_key_type, key_compare> after_key_members = get_key_members(a);
 
        vector<public_key_type> removed; removed.reserve(before_key_members.size());
        std::set_difference(before_key_members.begin(), before_key_members.end(),
diff --git a/libraries/chain/db_block.cpp b/libraries/chain/db_block.cpp
index e9124594e..42c15dc3e 100644
--- a/libraries/chain/db_block.cpp
+++ b/libraries/chain/db_block.cpp
@@ -672,9 +672,14 @@ processed_transaction database::_apply_transaction(const signed_transaction& trx
 
    auto& trx_idx = get_mutable_index_type<transaction_index>();
    const chain_id_type& chain_id = get_chain_id();
-   auto trx_id = trx.id();
-   FC_ASSERT( (skip & skip_transaction_dupe_check) ||
-              trx_idx.indices().get<by_trx_id>().find(trx_id) == trx_idx.indices().get<by_trx_id>().end() );
+   transaction_id_type trx_id;
+   
+   if( !(skip & skip_transaction_dupe_check) )
+   {
+      trx_id = trx.id();
+      FC_ASSERT( trx_idx.indices().get<by_trx_id>().find(trx_id) == trx_idx.indices().get<by_trx_id>().end() );
+   }
+
    transaction_evaluation_state eval_state(this);
    const chain_parameters& chain_parameters = get_global_properties().parameters;
    eval_state._trx = &trx;
@@ -708,7 +713,7 @@ processed_transaction database::_apply_transaction(const signed_transaction& trx
    //Insert transaction into unique transactions database.
    if( !(skip & skip_transaction_dupe_check) )
    {
-      create<transaction_object>([&](transaction_object& transaction) {
+      create<transaction_object>([&trx_id,&trx](transaction_object& transaction) {
          transaction.trx_id = trx_id;
          transaction.trx = trx;
       });
diff --git a/libraries/chain/include/graphene/chain/account_object.hpp b/libraries/chain/include/graphene/chain/account_object.hpp
index 914ade33d..36412d88d 100644
--- a/libraries/chain/include/graphene/chain/account_object.hpp
+++ b/libraries/chain/include/graphene/chain/account_object.hpp
@@ -278,6 +278,25 @@ namespace graphene { namespace chain {
     */
    class account_member_index : public secondary_index
    {
+      /* std::less::operator() is less efficient so using key_compare here.
+       * Let assume that it has two keys key1 and key2 and we want to insert key3.
+       * the insert function needs to first call std::less::operator() with key1 and key3.
+       * Assume std::less::operator()(key1, key3) returns false.
+       * It has to call std::less::operator() again with the keys switched, 
+       * std::less::operator()(key3, key1), to decide whether key1 is equal to key3 or 
+       * key3 is greater than key1. There are two calls to std::less::operator() to make
+       * a decision if the first call returns false.
+       * std::map::insert and std::set used key_compare, 
+       * there would be sufficient information to make the right decision using just one call.
+       */
+      class key_compare {
+      public:
+         inline bool operator()( const public_key_type& a, const public_key_type& b )const
+         {
+            return a.key_data < b.key_data;
+         }
+      };
+
       public:
          virtual void object_inserted( const object& obj ) override;
          virtual void object_removed( const object& obj ) override;
@@ -287,18 +306,18 @@ namespace graphene { namespace chain {
 
          /** given an account or key, map it to the set of accounts that reference it in an active or owner authority */
          map< account_id_type, set<account_id_type> > account_to_account_memberships;
-         map< public_key_type, set<account_id_type> > account_to_key_memberships;
+         map< public_key_type, set<account_id_type>, key_compare > account_to_key_memberships;
          /** some accounts use address authorities in the genesis block */
          map< address, set<account_id_type> >         account_to_address_memberships;
 
 
       protected:
          set<account_id_type>  get_account_members( const account_object& a )const;
-         set<public_key_type>  get_key_members( const account_object& a )const;
+         set<public_key_type, key_compare>  get_key_members( const account_object& a )const;
          set<address>          get_address_members( const account_object& a )const;
 
          set<account_id_type>  before_account_members;
-         set<public_key_type>  before_key_members;
+         set<public_key_type, key_compare>  before_key_members;
          set<address>          before_address_members;
    };