Improve vote tally performance

[abitmore]

Vote tally performance affects maintenance block producing (#504) as well as overall sync/replay time.

• Things we can do in short term:
  • skip those who are not voting,
  • skip those whose core_in_orders + core_balance is zero.

- [ ] Long term solution to be figured out.
- The mechanism used by Steem could be an option, but I think it only positively impacts maintenance block producing but probably negatively impacts overall sync/replay performance.

This is a sub-task of #982.

Update: moved long term job to issue #1204.

[oxarbitrage]

maybe it worth a new issue but can also fit here for initial conversation.

bitshares/open-explorer#31 (comment)

need to confirm if it is exactly whats happening but according to reported we may need to add a recalculating of votes into committee_members(and witnesses?) that are not active to update their voting count.

[abitmore]

Perhaps add a startup option or something that also update votes for inactive ones as well. Block producing nodes should not enable the option for better performance, but API nodes likely want to enable it..

[oxarbitrage]

yes, i added the comment in here as it will affect maint block latency even more but with the startup option it should not be a problem. thanks, making new issue for this and continue there, leaving this for increase performance only.

[abitmore]

Replay profiling data: https://pastebin.com/abmzjruy

---------------------- first 27 M blocks ----------------------------
1138060ms th_a db_management.cpp:124 reindex ] Done reindexing, elapsed time: 13812.88650899999993271 sec

Flat profile:
 
Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total
 time   seconds   seconds    calls   s/call   s/call  name
 25.25   1009.85  1009.85    22671     0.04     0.08  graphene::chain::database::perform_chain_maintenance(graphene::chain::signed_block const&, graphene::chain::global_property_object const&)
 11.16   1456.36   446.51 2148827443     0.00     0.00  graphene::chain::database::get_balance(graphene::db::object_id<(unsigned char)1, (unsigned char)2, graphene::chain::account_object>, graphene::db::object_id<(unsigned char)1, (unsigned char)3, graphene::chain::asset_object>) const
  7.27   1747.17   290.81 310082501     0.00     0.00  graphene::db::simple_index<graphene::chain::account_statistics_object>::find(graphene::db::object_id_type) const
  6.60   2011.04   263.87 386682199     0.00     0.00  graphene::chain::generic_index<graphene::chain::account_balance_object, ... >::modify(graphene::db::object const&, std::function<void (graphene::db::object&)> const&)
  5.04   2212.54   201.50 722779832     0.00     0.00  graphene::chain::generic_index<graphene::chain::account_object, ...  >::find(graphene::db::object_id_type) const
  4.33   2385.56   173.02 20731743387     0.00     0.00  graphene::chain::operator>(graphene::chain::price const&, graphene::chain::price const&)
  2.90   2501.68   116.12 390785433     0.00     0.00  graphene::chain::database::adjust_balance(graphene::db::object_id<(unsigned char)1, (unsigned char)2, graphene::chain::account_object>, graphene::chain::asset)
  2.60   2605.58   103.90 22967573183     0.00     0.00  graphene::chain::operator<(graphene::chain::price const&, graphene::chain::price const&)