diff --git a/core/blockchain.go b/core/blockchain.go
index 5fe2d5390d..217e3be9e0 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -153,7 +153,6 @@ type BlockChain struct {
 	chainmu sync.RWMutex // blockchain insertion lock
 	procmu  sync.RWMutex // block processor lock
 
-	checkpoint       int          // checkpoint counts towards the new checkpoint
 	currentBlock     atomic.Value // Current head of the block chain
 	currentFastBlock atomic.Value // Current head of the fast-sync chain (may be above the block chain!)
 
@@ -181,9 +180,8 @@ type BlockChain struct {
 	validator Validator // block and state validator interface
 	vmConfig  vm.Config
 
-	shouldPreserve func(*types.Block) bool // Function used to determine whether should preserve the given block.
-	IPCEndpoint    string
-	Client         bind.ContractBackend // Global ipc client instance.
+	IPCEndpoint string
+	Client      bind.ContractBackend // Global ipc client instance.
 
 	// Blocks hash array by block number
 	// cache field for tracking finality purpose, can't use for tracking block vs block relationship