fix Iterator leak, ref to https://github.com/cosmos/cosmos-sdk/issues/2105

examples/democoin/x/assoc/validator_set.go

@@ -93,6 +93,7 @@ func (valset ValidatorSet) Dissociate(ctx sdk.Context, base sdk.AccAddress, asso
 func (valset ValidatorSet) Associations(ctx sdk.Context, base sdk.AccAddress) (res []sdk.AccAddress) {
 	res = make([]sdk.AccAddress, valset.maxAssoc)
 	iter := sdk.KVStorePrefixIterator(valset.store, GetAssocPrefix(base))
+	defer iter.Close()
 	i := 0
 	for ; iter.Valid(); iter.Next() {
 		key := iter.Key()

examples/democoin/x/oracle/handler.go

@@ -28,6 +28,7 @@ func (keeper Keeper) update(ctx sdk.Context, val sdk.Validator, valset sdk.Valid
 		prefix := GetSignPrefix(p, keeper.cdc)
 		store := ctx.KVStore(keeper.key)
 		iter := sdk.KVStorePrefixIterator(store, prefix)
+		defer iter.Close()
 		for ; iter.Valid(); iter.Next() {
 			if valset.Validator(ctx, iter.Value()) != nil {
 				store.Delete(iter.Key())