planner: ignore lock for temporary table of PointGet and BatchPointGet (

#24540)

planner/core/integration_test.go

@@ -3832,3 +3832,29 @@ func (s *testIntegrationSerialSuite) TestEnforceMPP(c *C) {
 		"      └─Selection_20 10.00 285020.00 batchCop[tiflash]  eq(test.t.a, 1)",
 		"        └─TableFullScan_19 10000.00 255020.00 batchCop[tiflash] table:t keep order:false, stats:pseudo"))
 }
+
+func (s *testIntegrationSuite) TestEliminateLockForTemporaryTable(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+
+	tk.MustExec("use test;")
+	tk.MustExec("create global temporary table t1 (a int primary key, b int, c int, index i_b(b))  on commit delete rows;")
+	defer func() {
+		tk.MustExec("drop global temporary table if exists t1;")
+	}()
+	tk.MustExec("begin;")
+	tk.MustExec("insert t1 values (8,8,9);")
+
+	var input []string
+	var output []struct {
+		SQL  string
+		Plan []string
+	}
+	s.testData.GetTestCases(c, &input, &output)
+	for i, tt := range input {
+		s.testData.OnRecord(func() {
+			output[i].SQL = tt
+			output[i].Plan = s.testData.ConvertRowsToStrings(tk.MustQuery("explain format = 'brief' " + tt).Rows())
+		})
+		tk.MustQuery("explain format = 'brief' " + tt).Check(testkit.Rows(output[i].Plan...))
+	}
+}

planner/core/optimizer.go

@@ -20,6 +20,7 @@ import (
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/ast"
 	"github.com/pingcap/parser/auth"
+	"github.com/pingcap/parser/model"
 	"github.com/pingcap/parser/mysql"
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/expression"
@@ -186,6 +187,7 @@ func postOptimize(sctx sessionctx.Context, plan PhysicalPlan) PhysicalPlan {
 	plan = InjectExtraProjection(plan)
 	mergeContinuousSelections(plan)
 	plan = eliminateUnionScanAndLock(sctx, plan)
+	plan = eliminateLockForTemporaryTable(plan)
 	plan = enableParallelApply(sctx, plan)
 	return plan
 }
@@ -322,6 +324,29 @@ func eliminateUnionScanAndLock(sctx sessionctx.Context, p PhysicalPlan) Physical
 	})
 }
 
+// eliminateLockForTemporaryTable eliminates lock for the temporary table.
+func eliminateLockForTemporaryTable(p PhysicalPlan) PhysicalPlan {
+	iteratePhysicalPlan(p, func(p PhysicalPlan) bool {
+		if len(p.Children()) > 1 {
+			return false
+		}
+		switch x := p.(type) {
+		case *PointGetPlan:
+			if x.TblInfo.TempTableType != model.TempTableNone {
+				x.Lock = false
+				x.LockWaitTime = 0
+			}
+		case *BatchPointGetPlan:
+			if x.TblInfo.TempTableType != model.TempTableNone {
+				x.Lock = false
+				x.LockWaitTime = 0
+			}
+		}
+		return true
+	})
+	return p
+}
+
 func iteratePhysicalPlan(p PhysicalPlan, f func(p PhysicalPlan) bool) {
 	if !f(p) {
 		return

planner/core/point_get_plan.go

@@ -462,7 +462,10 @@ func TryFastPlan(ctx sessionctx.Context, node ast.Node) (p Plan) {
 			if tidbutil.IsMemDB(fp.dbName) {
 				return nil
 			}
-			fp.Lock, fp.LockWaitTime = getLockWaitTime(ctx, x.LockInfo)
+			// ignore lock for temporary table.
+			if fp.TblInfo.TempTableType == model.TempTableNone {
+				fp.Lock, fp.LockWaitTime = getLockWaitTime(ctx, x.LockInfo)
+			}
 			p = fp
 			return
 		}
@@ -480,7 +483,10 @@ func TryFastPlan(ctx sessionctx.Context, node ast.Node) (p Plan) {
 				p = tableDual.Init(ctx, &property.StatsInfo{}, 0)
 				return
 			}
-			fp.Lock, fp.LockWaitTime = getLockWaitTime(ctx, x.LockInfo)
+			// ignore lock for temporary table.
+			if fp.TblInfo.TempTableType == model.TempTableNone {
+				fp.Lock, fp.LockWaitTime = getLockWaitTime(ctx, x.LockInfo)
+			}
 			p = fp
 			return
 		}

planner/core/testdata/integration_suite_in.json

@@ -294,5 +294,14 @@
       "select sum(1) from s1",
       "select count(1) as cnt from s1 union select count(1) as cnt from s2"
     ]
+  },
+  {
+    "name": "TestEliminateLockForTemporaryTable",
+    "cases": [
+      "select * from t1 where a = 2 for update",
+      "select * from t1 where a in (1,2) for update",
+      "select c + 1 from t1 where a = 2 and c = 2 for update",
+      "select c + 1 from t1 where a in (1,2) and c = 2 for update"
+    ]
   }
 ]

planner/core/testdata/integration_suite_out.json

@@ -1564,5 +1564,38 @@
         ]
       }
     ]
+  },
+  {
+    "Name": "TestEliminateLockForTemporaryTable",
+    "Cases": [
+      {
+        "SQL": "select * from t1 where a = 2 for update",
+        "Plan": [
+          "Point_Get 1.00 root table:t1 handle:2"
+        ]
+      },
+      {
+        "SQL": "select * from t1 where a in (1,2) for update",
+        "Plan": [
+          "Batch_Point_Get 2.00 root table:t1 handle:[1 2], keep order:false, desc:false"
+        ]
+      },
+      {
+        "SQL": "select c + 1 from t1 where a = 2 and c = 2 for update",
+        "Plan": [
+          "Projection 0.00 root  plus(test.t1.c, 1)->Column#4",
+          "└─Selection 0.00 root  eq(test.t1.c, 2)",
+          "  └─Point_Get 1.00 root table:t1 handle:2"
+        ]
+      },
+      {
+        "SQL": "select c + 1 from t1 where a in (1,2) and c = 2 for update",
+        "Plan": [
+          "Projection 0.00 root  plus(test.t1.c, 1)->Column#4",
+          "└─Selection 0.00 root  eq(test.t1.c, 2)",
+          "  └─Batch_Point_Get 2.00 root table:t1 handle:[1 2], keep order:false, desc:false"
+        ]
+      }
+    ]
   }
 ]