Merge branch 'issue62' into issue357_upgrade

# Conflicts:
#	baseapp/options.go
#	store/iavlstore.go
#	types/store.go

store/iavlstore.go

@@ -66,10 +66,16 @@ func (st *IavlStore) Commit() CommitID {
 	}
 
 	// Release an old version of history, if not a sync waypoint.
-	for v, _ := range st.Tree.GetVersions() {
-		if st.pruningStrategy.Prune(v, version) {
-			st.Tree.DeleteVersion(v)
-		}
+	//for v, _ := range st.tree.GetVersions() {
+	//	if st.pruningStrategy.ShouldPrune(v, version) {
+	//		st.tree.DeleteVersion(v)
+	//	}
+	//}
+
+	// this is a special optimization for binance chain, 10001 should keep consistent with
+	// `numRecent` field of KeepRecentAndBreatheBlock
+	if version > 10001 && st.pruningStrategy.ShouldPrune(version-10001, version) {
+		st.tree.DeleteVersion(version - 10001)
 	}
 
 	return CommitID{

types/store.go

@@ -13,10 +13,11 @@ import (
 
 // PruningStrategy specfies how old states will be deleted over time
 type PruningStrategy interface {
-	Prune(version, latestVersion int64) bool
+	ShouldPrune(version, latestVersion int64) bool
 }
 
-// PruneSyncable means only those states not needed for state syncing will be deleted (keeps last 100 + every 10000th)
+// PruneSyncable defines the frequency (how many) of states would be saved,
+// while all the others are not needed for state syncing and would be deleted.
 type PruneSyncable struct {
 	// How many old versions we hold onto.
 	// A value of 0 means keep no recent states.
@@ -31,21 +32,21 @@ type PruneSyncable struct {
 	StoreEvery int64
 }
 
-func (strategy PruneSyncable) Prune(version, latestVersion int64) bool {
+func (strategy PruneSyncable) ShouldPrune(version, latestVersion int64) bool {
 	return (latestVersion-version > strategy.NumRecent) && (version%strategy.StoreEvery != 0)
 }
 
 // PruneEverything means all saved states will be deleted, storing only the current state
 type PruneEverything struct{}
 
-func (strategy PruneEverything) Prune(version, latestVersion int64) bool {
+func (strategy PruneEverything) ShouldPrune(version, latestVersion int64) bool {
 	return true
 }
 
 // PruneNothing means all historic states will be saved, nothing will be deleted
 type PruneNothing struct{}
 
-func (strategy PruneNothing) Prune(version, latestVersion int64) bool {
+func (strategy PruneNothing) ShouldPrune(version, latestVersion int64) bool {
 	return false
 }