Clean up store versions after a limit

app/store.go

@@ -17,6 +17,9 @@ import (
 	sm "github.com/cosmos/cosmos-sdk/state"
 )
 
+// DefaultHistorySize is how many blocks of history to store for ABCI queries
+const DefaultHistorySize = 10
+
 // StoreApp contains a data store and all info needed
 // to perform queries and handshakes.
 //
@@ -41,7 +44,7 @@ type StoreApp struct {
 
 // NewStoreApp creates a data store to handle queries
 func NewStoreApp(appName, dbName string, cacheSize int, logger log.Logger) (*StoreApp, error) {
-	state, err := loadState(dbName, cacheSize)
+	state, err := loadState(dbName, cacheSize, DefaultHistorySize)
 	if err != nil {
 		return nil, err
 	}
@@ -234,11 +237,11 @@ func pubKeyIndex(val *abci.Validator, list []*abci.Validator) int {
 	return -1
 }
 
-func loadState(dbName string, cacheSize int) (*sm.State, error) {
+func loadState(dbName string, cacheSize int, historySize uint64) (*sm.State, error) {
 	// memory backed case, just for testing
 	if dbName == "" {
 		tree := iavl.NewVersionedTree(0, dbm.NewMemDB())
-		return sm.NewState(tree), nil
+		return sm.NewState(tree, historySize), nil
 	}
 
 	// Expand the path fully
@@ -267,5 +270,5 @@ func loadState(dbName string, cacheSize int) (*sm.State, error) {
 		}
 	}
 
-	return sm.NewState(tree), nil
+	return sm.NewState(tree, historySize), nil
 }

state/merkle.go

@@ -5,17 +5,19 @@ import "github.com/tendermint/iavl"
 // State represents the app states, separating the commited state (for queries)
 // from the working state (for CheckTx and AppendTx)
 type State struct {
-	committed *Bonsai
-	deliverTx SimpleDB
-	checkTx   SimpleDB
+	committed   *Bonsai
+	deliverTx   SimpleDB
+	checkTx     SimpleDB
+	historySize uint64
 }
 
-func NewState(tree *iavl.VersionedTree) *State {
+func NewState(tree *iavl.VersionedTree, historySize uint64) *State {
 	base := NewBonsai(tree)
 	return &State{
-		committed: base,
-		deliverTx: base.Checkpoint(),
-		checkTx:   base.Checkpoint(),
+		committed:   base,
+		deliverTx:   base.Checkpoint(),
+		checkTx:     base.Checkpoint(),
+		historySize: historySize,
 	}
 }
 
@@ -51,6 +53,7 @@ func (s *State) Commit(version uint64) ([]byte, error) {
 		return nil, err
 	}
 
+	// store a new version
 	var hash []byte
 	if s.committed.Tree.Size() > 0 || s.committed.Tree.LatestVersion() > 0 {
 		hash, err = s.committed.Tree.SaveVersion(version)
@@ -59,6 +62,11 @@ func (s *State) Commit(version uint64) ([]byte, error) {
 		}
 	}
 
+	// release an old version
+	if version > s.historySize {
+		s.committed.Tree.DeleteVersion(version - s.historySize)
+	}
+
 	s.deliverTx = s.committed.Checkpoint()
 	s.checkTx = s.committed.Checkpoint()
 	return hash, nil

state/merkle_test.go

@@ -66,7 +66,7 @@ func TestStateCommitHash(t *testing.T) {
 
 			// make the store...
 			tree := iavl.NewVersionedTree(0, db.NewMemDB())
-			store := NewState(tree)
+			store := NewState(tree, 2)
 
 			for n, r := range tc.rounds {
 				// start the cache