fix earned-reward per key by temporary persisting stats and writing at once (#2693)

sorted slice of map for deterministic write

core/offchain.go

@@ -1,7 +1,9 @@
 package core
 
 import (
+	"bytes"
 	"math/big"
+	"sort"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/rlp"
@@ -12,6 +14,7 @@ import (
 	"github.com/harmony-one/harmony/internal/utils"
 	"github.com/harmony-one/harmony/shard"
 	"github.com/harmony-one/harmony/staking/slash"
+	staking "github.com/harmony-one/harmony/staking/types"
 	"github.com/pkg/errors"
 )
 
@@ -214,36 +217,56 @@ func (bc *BlockChain) CommitOffChainData(
 			); err != nil {
 				return NonStatTy, err
 			}
-
+			tempValidatorStats := map[common.Address]*staking.ValidatorStats{}
 			for _, paid := range [...][]reward.Payout{
 				roundResult.BeaconchainAward, roundResult.ShardChainAward,
 			} {
 				for i := range paid {
-					if stats, err := bc.ReadValidatorStats(paid[i].Addr); err == nil {
-						doUpdate := false
+					stats, ok := tempValidatorStats[paid[i].Addr]
+					if !ok {
+						stats, err = bc.ReadValidatorStats(paid[i].Addr)
+						if err != nil {
+							utils.Logger().Info().Err(err).
+								Str("bls-earning-key", paid[i].EarningKey.Hex()).
+								Msg("could not read validator stats to update for earning per key")
+							continue
+						}
+						tempValidatorStats[paid[i].Addr] = stats
+					}
 					for j := range stats.MetricsPerShard {
 						if stats.MetricsPerShard[j].Vote.Identity == paid[i].EarningKey {
-								doUpdate = true
 							stats.MetricsPerShard[j].Earned.Add(
 								stats.MetricsPerShard[j].Earned,
 								paid[i].NewlyEarned,
 							)
 						}
 					}
-						if doUpdate {
-							if err := rawdb.WriteValidatorStats(
-								batch, paid[i].Addr, stats,
-							); err != nil {
-								utils.Logger().Info().Err(err).
-									Str("bls-earning-key", paid[i].EarningKey.Hex()).
-									Msg("could not update earning per key in stats")
+
 				}
 			}
-					} else {
-						utils.Logger().Info().Err(err).
-							Str("bls-earning-key", paid[i].EarningKey.Hex()).
-							Msg("could not read validator stats to update for earning per key")
+			type t struct {
+				addr  common.Address
+				stats *staking.ValidatorStats
 			}
+			sortedStats := []t{}
+			for key, value := range tempValidatorStats {
+				sortedStats = append(sortedStats, t{key, value})
+			}
+			sort.SliceStable(
+				sortedStats,
+				func(i, j int) bool {
+					return bytes.Compare(
+						sortedStats[i].addr[:], sortedStats[j].addr[:],
+					) == -1
+				},
+			)
+			for _, stat := range sortedStats {
+				if err := rawdb.WriteValidatorStats(
+					batch, stat.addr, stat.stats,
+				); err != nil {
+					utils.Logger().Info().Err(err).
+						Str("validator address", stat.addr.Hex()).
+						Msg("could not update stats for validator")
 				}
 			}