server: forget to add StmtCommit when loading data (pingcap#5758)

server/conn.go

@@ -729,6 +729,7 @@ func insertDataWithCommit(goCtx goctx.Context, prevData, curData []byte, loadDat
 		if !reachLimit {
 			break
 		}
+		terror.Log(loadDataInfo.Ctx.StmtCommit())
 		// Make sure that there are no retries when committing.
 		if err = loadDataInfo.Ctx.RefreshTxnCtx(goCtx); err != nil {
 			return nil, errors.Trace(err)

server/server_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/go-sql-driver/mysql"
 	. "github.com/pingcap/check"
 	"github.com/pingcap/tidb/executor"
+	"github.com/pingcap/tidb/kv"
 	tmysql "github.com/pingcap/tidb/mysql"
 	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tidb/util/printer"
@@ -322,6 +323,11 @@ func runTestLoadData(c *C, server *Server) {
 		"xxx row5_col1	- 	row5_col3")
 	c.Assert(err, IsNil)
 
+	originalTxnTotalSizeLimit := kv.TxnTotalSizeLimit
+	// If the MemBuffer can't be committed once in each batch, it will return an error like "transaction is too large".
+	kv.TxnTotalSizeLimit = 10240
+	defer func() { kv.TxnTotalSizeLimit = originalTxnTotalSizeLimit }()
+
 	// support ClientLocalFiles capability
 	runTestsOnNewDB(c, func(config *mysql.Config) {
 		config.AllowAllFiles = true