executor: fix point get -1 return max.uInt64 value (pingcap#10113)

Author: lysu

executor/point_get.go

@@ -46,6 +46,7 @@ func (b *executorBuilder) buildPointGet(p *plannercore.PointGetPlan) Executor {
 		idxVals: p.IndexValues,
 		handle:  p.Handle,
 		startTS: startTS,
+		done:    p.UnsignedHandle && p.Handle < 0,
 	}
 }
 

planner/core/point_get_plan.go

@@ -41,6 +41,7 @@ type PointGetPlan struct {
 	IndexInfo        *model.IndexInfo
 	Handle           int64
 	HandleParam      *driver.ParamMarkerExpr
+	UnsignedHandle   bool
 	IndexValues      []types.Datum
 	IndexValueParams []*driver.ParamMarkerExpr
 	expr             expression.Expression
@@ -185,7 +186,7 @@ func tryPointGetPlan(ctx sessionctx.Context, selStmt *ast.SelectStmt) *PointGetP
 	if pairs == nil {
 		return nil
 	}
-	handlePair := findPKHandle(tbl, pairs)
+	handlePair, unsigned := findPKHandle(tbl, pairs)
 	if handlePair.value.Kind() != types.KindNull && len(pairs) == 1 {
 		schema := buildSchemaFromFields(ctx, tblName.Schema, tbl, selStmt.Fields.Fields)
 		if schema == nil {
@@ -197,6 +198,7 @@ func tryPointGetPlan(ctx sessionctx.Context, selStmt *ast.SelectStmt) *PointGetP
 		if err != nil {
 			return nil
 		}
+		p.UnsignedHandle = unsigned
 		p.HandleParam = handlePair.param
 		return p
 	}
@@ -362,20 +364,20 @@ func getNameValuePairs(nvPairs []nameValuePair, expr ast.ExprNode) []nameValuePa
 	return nil
 }
 
-func findPKHandle(tblInfo *model.TableInfo, pairs []nameValuePair) (handlePair nameValuePair) {
+func findPKHandle(tblInfo *model.TableInfo, pairs []nameValuePair) (handlePair nameValuePair, unsigned bool) {
 	if !tblInfo.PKIsHandle {
-		return handlePair
+		return handlePair, unsigned
 	}
 	for _, col := range tblInfo.Columns {
 		if mysql.HasPriKeyFlag(col.Flag) {
 			i := findInPairs(col.Name.L, pairs)
 			if i == -1 {
-				return handlePair
+				return handlePair, unsigned
 			}
-			return pairs[i]
+			return pairs[i], mysql.HasUnsignedFlag(col.Flag)
 		}
 	}
-	return handlePair
+	return handlePair, unsigned
 }
 
 func getIndexValues(idxInfo *model.IndexInfo, pairs []nameValuePair) ([]types.Datum, []*driver.ParamMarkerExpr) {

planner/core/point_get_plan_test.go

@@ -54,7 +54,7 @@ func (s *testPointGetSuite) TestPointGetPlanCache(c *C) {
 	core.PreparedPlanCacheMaxMemory.Store(math.MaxUint64)
 	tk.MustExec("use test")
 	tk.MustExec("drop table if exists t")
-	tk.MustExec("create table t(a int primary key, b int, c int, key idx_bc(b,c))")
+	tk.MustExec("create table t(a bigint unsigned primary key, b int, c int, key idx_bc(b,c))")
 	tk.MustExec("insert into t values(1, 1, 1), (2, 2, 2), (3, 3, 3)")
 	tk.MustQuery("explain select * from t where a = 1").Check(testkit.Rows(
 		"Point_Get_1 1.00 root table:t, handle:1",
@@ -68,6 +68,11 @@ func (s *testPointGetSuite) TestPointGetPlanCache(c *C) {
 	tk.MustQuery("explain delete from t where a = 1").Check(testkit.Rows(
 		"Point_Get_1 1.00 root table:t, handle:1",
 	))
+	tk.MustQuery("explain select a from t where a = -1").Check(testkit.Rows(
+		"TableDual_5 0.00 root rows:0"))
+	tk.MustExec(`prepare stmt0 from "select a from t where a = ?"`)
+	tk.MustExec("set @p0 = -1")
+	tk.MustQuery("execute stmt0 using @p0").Check(testkit.Rows())
 	metrics.ResettablePlanCacheCounterFortTest = true
 	metrics.PlanCacheCounter.Reset()
 	counter := metrics.PlanCacheCounter.WithLabelValues("prepare")
@@ -137,4 +142,13 @@ func (s *testPointGetSuite) TestPointGetPlanCache(c *C) {
 	counter.Write(pb)
 	hit = pb.GetCounter().GetValue()
 	c.Check(hit, Equals, float64(2))
+	tk.MustExec("insert into t (a, b, c) values (18446744073709551615, 4, 4)")
+	tk.MustExec("set @p1=-1")
+	tk.MustExec("set @p2=1")
+	tk.MustExec(`prepare stmt7 from "select a from t where a = ?"`)
+	tk.MustQuery("execute stmt7 using @p1").Check(testkit.Rows())
+	tk.MustQuery("execute stmt7 using @p2").Check(testkit.Rows("1"))
+	counter.Write(pb)
+	hit = pb.GetCounter().GetValue()
+	c.Check(hit, Equals, float64(3))
 }