store/tikv: remove Variables.Hook

session/session_fail_test.go

@@ -15,11 +15,11 @@ package session_test
 
 import (
 	"context"
-	"sync/atomic"
+	"strings"
 
 	. "github.com/pingcap/check"
 	"github.com/pingcap/failpoint"
-	"github.com/pingcap/tidb/store/tikv"
+	"github.com/pingcap/tidb/session"
 	"github.com/pingcap/tidb/util/testkit"
 )
 
@@ -79,20 +79,19 @@ func (s *testSessionSerialSuite) TestGetTSFailDirtyStateInretry(c *C) {
 
 func (s *testSessionSerialSuite) TestKillFlagInBackoff(c *C) {
 	// This test checks the `killed` flag is passed down to the backoffer through
-	// session.KVVars. It works by setting the `killed = 3` first, then using
-	// failpoint to run backoff() and check the vars.Killed using the Hook() function.
+	// session.KVVars.
 	tk := testkit.NewTestKitWithInit(c, s.store)
 	tk.MustExec("create table kill_backoff (id int)")
-	var killValue uint32
-	tk.Se.GetSessionVars().KVVars.Hook = func(name string, vars *tikv.Variables) {
-		killValue = atomic.LoadUint32(vars.Killed)
-	}
-	c.Assert(failpoint.Enable("github.com/pingcap/tidb/store/tikv/tikvStoreSendReqResult", `return("callBackofferHook")`), IsNil)
+	// Inject 1 time timeout. If `Killed` is not successfully passed, it will retry and complete query.
+	c.Assert(failpoint.Enable("github.com/pingcap/tidb/store/tikv/tikvStoreSendReqResult", `return("timeout")->return("")`), IsNil)
 	defer failpoint.Disable("github.com/pingcap/tidb/store/tikv/tikvStoreSendReqResult")
 	// Set kill flag and check its passed to backoffer.
-	tk.Se.GetSessionVars().Killed = 3
-	tk.MustQuery("select * from kill_backoff")
-	c.Assert(killValue, Equals, uint32(3))
+	tk.Se.GetSessionVars().Killed = 1
+	rs, err := tk.Exec("select * from kill_backoff")
+	c.Assert(err, IsNil)
+	_, err = session.ResultSetToStringSlice(context.TODO(), tk.Se, rs)
+	// `interrupted` is returned when `Killed` is set.
+	c.Assert(strings.Contains(err.Error(), "Query execution was interrupted"), IsTrue)
 }
 
 func (s *testSessionSerialSuite) TestClusterTableSendError(c *C) {

store/tikv/kv/variables.go

@@ -21,9 +21,6 @@ type Variables struct {
 	// BackOffWeight specifies the weight of the max back off time duration.
 	BackOffWeight int
 
-	// Hook is used for test to verify the variable take effect.
-	Hook func(name string, vars *Variables)
-
 	// Pointer to SessionVars.Killed
 	// Killed is a flag to indicate that this query is killed.
 	Killed *uint32

store/tikv/region_request.go

@@ -248,8 +248,6 @@ func (s *RegionRequestSender) SendReqCtx(
 					Resp: &kvrpcpb.GCResponse{RegionError: &errorpb.Error{ServerIsBusy: &errorpb.ServerIsBusy{}}},
 				}, nil, nil)
 			}
-		case "callBackofferHook":
-			bo.SetVarsHook("callBackofferHook", bo.GetVars())
 		case "requestTiDBStoreError":
 			if et == tikvrpc.TiDB {
 				failpoint.Return(nil, nil, tikverr.ErrTiKVServerTimeout)

store/tikv/retry/backoff.go

@@ -135,9 +135,6 @@ const (
 )
 
 func (t BackoffType) createFn(vars *kv.Variables) func(context.Context, int) int {
-	if vars.Hook != nil {
-		vars.Hook(t.String(), vars)
-	}
 	switch t {
 	case boTiKVRPC, BoTiFlashRPC:
 		return NewBackoffFn(100, 2000, EqualJitter)
@@ -431,10 +428,3 @@ func (b *Backoffer) GetBackoffSleepMS() map[BackoffType]int {
 func (b *Backoffer) ErrorsNum() int {
 	return len(b.errors)
 }
-
-// SetVarsHook sets the vars.Hook is used for test to verify the variable take effect.
-func (b *Backoffer) SetVarsHook(name string, vars *kv.Variables) {
-	if b.vars != nil && b.vars.Hook != nil {
-		b.vars.Hook(name, vars)
-	}
-}