Improve index on account operation history

- operations are now indexed by account and sequence for effecient
traversal and query

libraries/chain/include/graphene/chain/account_object.hpp

@@ -47,6 +47,7 @@ namespace graphene { namespace chain {
           * Keep the most recent operation as a root pointer to a linked list of the transaction history.
           */
          account_transaction_history_id_type most_recent_op;
+         uint32_t                            total_ops = 0;
 
          /**
           * When calculating votes it is necessary to know how much is stored in orders (and thus unavailable for
@@ -342,6 +343,7 @@ FC_REFLECT_DERIVED( graphene::chain::account_statistics_object,
                     (graphene::chain::object),
                     (owner)
                     (most_recent_op)
+                    (total_ops)
                     (total_core_in_orders)
                     (lifetime_fees_paid)
                     (pending_fees)(pending_vested_fees)

libraries/chain/include/graphene/chain/operation_history_object.hpp

@@ -86,8 +86,13 @@ namespace graphene { namespace chain {
       public:
          static const uint8_t space_id = implementation_ids;
          static const uint8_t type_id  = impl_account_transaction_history_object_type;
+         account_id_type                      account; /// the account this operation applies to
          operation_history_id_type            operation_id;
+         uint32_t                             sequence = 0; /// the operation position within the given account
          account_transaction_history_id_type  next;
+
+         std::pair<account_id_type,operation_history_id_type>  account_op()const  { return std::tie( account, operation_id ); }
+         std::pair<account_id_type,uint32_t>                   account_seq()const { return std::tie( account, sequence );     }
    };
 } } // graphene::chain
 
@@ -95,4 +100,4 @@ FC_REFLECT_DERIVED( graphene::chain::operation_history_object, (graphene::chain:
                     (op)(result)(block_num)(trx_in_block)(op_in_trx)(virtual_op) )
 
 FC_REFLECT_DERIVED( graphene::chain::account_transaction_history_object, (graphene::chain::object),
-                    (operation_id)(next) )
+                    (account)(operation_id)(sequence)(next) )

libraries/plugins/account_history/account_history_plugin.cpp

@@ -105,10 +105,13 @@ void account_history_plugin_impl::update_account_histories( const signed_block&
             const auto& stats_obj = account_id(db).statistics(db);
             const auto& ath = db.create<account_transaction_history_object>( [&]( account_transaction_history_object& obj ){
                 obj.operation_id = oho.id;
+                obj.account = account_id;
+                obj.sequence = stats_obj.total_ops+1;
                 obj.next = stats_obj.most_recent_op;
             });
             db.modify( stats_obj, [&]( account_statistics_object& obj ){
                 obj.most_recent_op = ath.id;
+                obj.total_ops = ath.sequence;
             });
          }
       }
@@ -134,6 +137,35 @@ void account_history_plugin_impl::update_account_histories( const signed_block&
 }
 } // end namespace detail
 
+
+struct by_id;
+struct by_seq;
+struct by_op;
+typedef multi_index_container<
+  account_transaction_history_object,
+  indexed_by<
+     ordered_unique< tag<by_id>,
+        member< object, object_id_type, &object::id > >,
+     ordered_unique< tag<by_seq>,
+        composite_key< account_transaction_history_object,
+           member< account_transaction_history_object, account_id_type, &account_transaction_history_object::account>,
+           member< account_transaction_history_object, uint32_t, &account_transaction_history_object::sequence>
+        >
+     >,
+     ordered_unique< tag<by_op>,
+        composite_key< account_transaction_history_object,
+           member< account_transaction_history_object, account_id_type, &account_transaction_history_object::account>,
+           member< account_transaction_history_object, operation_history_id_type, &account_transaction_history_object::operation_id>
+        >
+     >
+  >
+> account_transaction_history_multi_index_type;
+
+typedef generic_index<account_transaction_history_object, account_transaction_history_multi_index_type> account_transaction_history_index;
+
+
+
+
 account_history_plugin::account_history_plugin() :
    my( new detail::account_history_plugin_impl(*this) )
 {
@@ -163,7 +195,7 @@ void account_history_plugin::plugin_initialize(const boost::program_options::var
 {
    database().applied_block.connect( [&]( const signed_block& b){ my->update_account_histories(b); } );
    database().add_index< primary_index< simple_index< operation_history_object > > >();
-   database().add_index< primary_index< simple_index< account_transaction_history_object > > >();
+   database().add_index< primary_index< account_transaction_history_index > >();
 
    LOAD_VALUE_SET(options, "tracked-accounts", my->_tracked_accounts, graphene::chain::account_id_type);
 }