From 40f19cb0b3b199e7657f8e017ad59a4f48febce7 Mon Sep 17 00:00:00 2001
From: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
Date: Tue, 21 Jun 2022 09:58:36 +0800
Subject: [PATCH] system_variables: remove the limitation for set
 tidb_gc_life_time (#35411) (#35467)

close pingcap/tidb#35392
---
 executor/set_test.go            | 16 ++++++++++++++++
 sessionctx/variable/sysvar.go   | 15 +++++----------
 sessionctx/variable/varsutil.go | 33 ---------------------------------
 3 files changed, 21 insertions(+), 43 deletions(-)

diff --git a/executor/set_test.go b/executor/set_test.go
index e06ab579be68e..dcc80182841eb 100644
--- a/executor/set_test.go
+++ b/executor/set_test.go
@@ -1702,3 +1702,19 @@ func TestInstanceScopeSwitching(t *testing.T) {
 	tk.MustExec("set tidb_enable_legacy_instance_scope = 0")
 	tk.MustGetErrCode("set tidb_general_log = 1", errno.ErrGlobalVariable)
 }
+
+func TestGcMaxWaitTime(t *testing.T) {
+	store, clean := testkit.CreateMockStore(t)
+	defer clean()
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+
+	tk.MustExec("set global tidb_gc_max_wait_time = 1000")
+	tk.MustExec("set global tidb_gc_life_time = \"72h\"")
+	tk.MustExec("set global tidb_gc_life_time = \"24h\"")
+	tk.MustExec("set global tidb_gc_life_time = \"10m\"")
+
+	tk.MustExec("set global tidb_gc_max_wait_time = 86400")
+	tk.MustExec("set global tidb_gc_life_time = \"72h\"")
+	tk.MustExec("set global tidb_gc_max_wait_time = 1000")
+}
diff --git a/sessionctx/variable/sysvar.go b/sessionctx/variable/sysvar.go
index 9cdb8f8a7dd49..169b1be0feec7 100644
--- a/sessionctx/variable/sysvar.go
+++ b/sessionctx/variable/sysvar.go
@@ -583,9 +583,7 @@ var defaultSysVars = []*SysVar{
 	}, SetGlobal: func(s *SessionVars, val string) error {
 		return setTiDBTableValue(s, "tikv_gc_run_interval", val, "GC run interval, at least 10m, in Go format.")
 	}},
-	{Scope: ScopeGlobal, Name: TiDBGCLifetime, Value: "10m0s", Type: TypeDuration, MinValue: int64(time.Minute * 10), MaxValue: uint64(time.Hour * 24 * 365), Validation: func(vars *SessionVars, normalizedValue string, originalValue string, scope ScopeFlag) (string, error) {
-		return checkTiKVGCLifeTime(vars, normalizedValue, originalValue, scope)
-	}, GetGlobal: func(s *SessionVars) (string, error) {
+	{Scope: ScopeGlobal, Name: TiDBGCLifetime, Value: "10m0s", Type: TypeDuration, MinValue: int64(time.Minute * 10), MaxValue: uint64(time.Hour * 24 * 365), GetGlobal: func(s *SessionVars) (string, error) {
 		return getTiDBTableValue(s, "tikv_gc_life_time", "10m0s")
 	}, SetGlobal: func(s *SessionVars, val string) error {
 		return setTiDBTableValue(s, "tikv_gc_life_time", val, "All versions within life time will not be collected by GC, at least 10m, in Go format.")
@@ -612,13 +610,10 @@ var defaultSysVars = []*SysVar{
 	}, SetGlobal: func(s *SessionVars, val string) error {
 		return setTiDBTableValue(s, "tikv_gc_scan_lock_mode", val, "Mode of scanning locks, \"physical\" or \"legacy\"")
 	}},
-	{Scope: ScopeGlobal, Name: TiDBGCMaxWaitTime, Value: strconv.Itoa(DefTiDBGCMaxWaitTime), Type: TypeInt, MinValue: 600, MaxValue: 31536000,
-		Validation: func(vars *SessionVars, normalizedValue string, originalValue string, scope ScopeFlag) (string, error) {
-			return checkGCTxnMaxWaitTime(vars, normalizedValue, originalValue, scope)
-		}, SetGlobal: func(s *SessionVars, val string) error {
-			GCMaxWaitTime.Store(TidbOptInt64(val, DefTiDBGCMaxWaitTime))
-			return nil
-		}},
+	{Scope: ScopeGlobal, Name: TiDBGCMaxWaitTime, Value: strconv.Itoa(DefTiDBGCMaxWaitTime), Type: TypeInt, MinValue: 600, MaxValue: 31536000, SetGlobal: func(s *SessionVars, val string) error {
+		GCMaxWaitTime.Store(TidbOptInt64(val, DefTiDBGCMaxWaitTime))
+		return nil
+	}},
 	{Scope: ScopeGlobal, Name: TiDBTableCacheLease, Value: strconv.Itoa(DefTiDBTableCacheLease), Type: TypeUnsigned, MinValue: 1, MaxValue: 10, SetGlobal: func(s *SessionVars, sVal string) error {
 		var val int64
 		val, err := strconv.ParseInt(sVal, 10, 64)
diff --git a/sessionctx/variable/varsutil.go b/sessionctx/variable/varsutil.go
index 495fc1f4d5b58..39ec20cbe2fb1 100644
--- a/sessionctx/variable/varsutil.go
+++ b/sessionctx/variable/varsutil.go
@@ -512,36 +512,3 @@ var GAFunction4ExpressionIndex = map[string]struct{}{
 	ast.VitessHash: {},
 	ast.TiDBShard:  {},
 }
-
-func checkGCTxnMaxWaitTime(vars *SessionVars,
-	normalizedValue string,
-	originalValue string,
-	scope ScopeFlag) (string, error) {
-	ival, err := strconv.Atoi(normalizedValue)
-	if err != nil {
-		return originalValue, errors.Trace(err)
-	}
-	GcLifeTimeStr, _ := getTiDBTableValue(vars, "tikv_gc_life_time", "10m0s")
-	GcLifeTimeDuration, err := time.ParseDuration(GcLifeTimeStr)
-	if err != nil {
-		return originalValue, errors.Trace(err)
-	}
-	if GcLifeTimeDuration.Seconds() > (float64)(ival) {
-		return originalValue, errors.Trace(ErrWrongValueForVar.GenWithStackByArgs(TiDBGCMaxWaitTime, normalizedValue))
-	}
-	return normalizedValue, nil
-}
-
-func checkTiKVGCLifeTime(vars *SessionVars,
-	normalizedValue string,
-	originalValue string,
-	scope ScopeFlag) (string, error) {
-	gcLifetimeDuration, err := time.ParseDuration(normalizedValue)
-	if err != nil {
-		return originalValue, errors.Trace(err)
-	}
-	if gcLifetimeDuration.Seconds() > float64(GCMaxWaitTime.Load()) {
-		return originalValue, errors.Trace(ErrWrongValueForVar.GenWithStackByArgs(TiDBGCLifetime, normalizedValue))
-	}
-	return normalizedValue, nil
-}