diff --git a/apiserver/controllers/block.go b/apiserver/controllers/block.go
index 90c413d29..0024992a8 100644
--- a/apiserver/controllers/block.go
+++ b/apiserver/controllers/block.go
@@ -2,11 +2,12 @@ package controllers
 
 import (
 	"encoding/hex"
+	"net/http"
+
 	"github.com/daglabs/btcd/apiserver/apimodels"
 	"github.com/daglabs/btcd/apiserver/dbmodels"
 	"github.com/daglabs/btcd/httpserverutils"
 	"github.com/pkg/errors"
-	"net/http"
 
 	"github.com/daglabs/btcd/apiserver/database"
 	"github.com/daglabs/btcd/util/daghash"
@@ -45,7 +46,8 @@ func GetBlockByHashHandler(blockHash string) (interface{}, error) {
 		return nil, httpserverutils.NewHandlerError(http.StatusNotFound, errors.New("No block with the given block hash was found"))
 	}
 	if httpserverutils.HasDBError(dbErrors) {
-		return nil, httpserverutils.NewErrorFromDBErrors("Some errors were encountered when loading transactions from the database:", dbResult.GetErrors())
+		return nil, httpserverutils.NewErrorFromDBErrors("Some errors were encountered when loading transactions from the database:",
+			dbResult.GetErrors())
 	}
 	return convertBlockModelToBlockResponse(block), nil
 }
diff --git a/apiserver/sync.go b/apiserver/sync.go
index d09878600..942fe8214 100644
--- a/apiserver/sync.go
+++ b/apiserver/sync.go
@@ -147,13 +147,13 @@ func syncSelectedParentChain(client *jsonrpc.Client) error {
 // blue score in the database. If the database is empty,
 // return nil.
 func findHashOfBluestBlock(mustBeChainBlock bool) (*string, error) {
-	dbTx, err := database.DB()
+	db, err := database.DB()
 	if err != nil {
 		return nil, err
 	}
 
 	var block dbmodels.Block
-	dbQuery := dbTx.Order("blue_score DESC")
+	dbQuery := db.Order("blue_score DESC")
 	if mustBeChainBlock {
 		dbQuery = dbQuery.Where(&dbmodels.Block{IsChainBlock: true})
 	}
@@ -226,6 +226,7 @@ func addBlock(client *jsonrpc.Client, block string, rawBlock btcjson.GetBlockVer
 		return err
 	}
 	dbTx := db.Begin()
+	defer dbTx.RollbackUnlessCommitted()
 
 	// Skip this block if it already exists.
 	blockExists, err := doesBlockExist(dbTx, rawBlock.Hash)
@@ -703,6 +704,7 @@ func updateSelectedParentChain(removedChainHashes []string, addedChainBlocks []b
 		return err
 	}
 	dbTx := db.Begin()
+	defer dbTx.RollbackUnlessCommitted()
 
 	for _, removedHash := range removedChainHashes {
 		err := updateRemovedChainHashes(dbTx, removedHash)
@@ -949,7 +951,7 @@ func processChainChangedMsgs() {
 // canHandleChainChangedMsg checks whether we have all the necessary data
 // to successfully handle a ChainChangedMsg.
 func canHandleChainChangedMsg(chainChanged *jsonrpc.ChainChangedMsg) (bool, error) {
-	dbTx, err := database.DB()
+	db, err := database.DB()
 	if err != nil {
 		return false, err
 	}
@@ -965,7 +967,7 @@ func canHandleChainChangedMsg(chainChanged *jsonrpc.ChainChangedMsg) (bool, erro
 
 	// Make sure that all the hashes exist in the database
 	var dbBlocks []dbmodels.Block
-	dbResult := dbTx.
+	dbResult := db.
 		Model(&dbmodels.Block{}).
 		Where("block_hash in (?)", hashesIn).
 		Find(&dbBlocks)