planner: skip plan-cache for prepared queries with `INT in (Decimals.…

…..)` (#40312) (#40691)

close #40224

planner/core/expression_rewriter.go

@@ -1550,17 +1550,11 @@ func (er *expressionRewriter) inToExpression(lLen int, not bool, tp *types.Field
 			if c, ok := args[i].(*expression.Constant); ok {
 				var isExceptional bool
 				if expression.MaybeOverOptimized4PlanCache(er.sctx, []expression.Expression{c}) {
-					if c.GetType().EvalType() == types.ETString {
-						// To keep the result be compatible with MySQL, refine `int non-constant <cmp> str constant`
-						// here and skip this refine operation in all other cases for safety.
-						er.sctx.GetSessionVars().StmtCtx.SkipPlanCache = true
-						er.sctx.GetSessionVars().StmtCtx.AppendWarning(errors.Errorf("skip plan-cache: '%v' may be converted to INT", c.String()))
-						expression.RemoveMutableConst(er.sctx, []expression.Expression{c})
-					} else {
-						continue
+					if c.GetType().EvalType() == types.ETInt {
+						continue // no need to refine it
 					}
-				} else if er.sctx.GetSessionVars().StmtCtx.SkipPlanCache {
-					// We should remove the mutable constant for correctness, because its value may be changed.
+					er.sctx.GetSessionVars().StmtCtx.SkipPlanCache = true
+					er.sctx.GetSessionVars().StmtCtx.AppendWarning(errors.Errorf("skip plan-cache: '%v' may be converted to INT", c.String()))
 					expression.RemoveMutableConst(er.sctx, []expression.Expression{c})
 				}
 				args[i], isExceptional = expression.RefineComparedConstant(er.sctx, *leftFt, c, opcode.EQ)

planner/core/plan_cache_test.go

@@ -313,3 +313,35 @@ func TestPlanCacheDiagInfo(t *testing.T) {
 	tk.MustExec("execute stmt using @a, @b") // a=1 and a=1 -> a=1
 	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1105 skip plan-cache: some parameters may be overwritten"))
 }
+
+func TestIssue40224(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t (a int, key(a))")
+	tk.MustExec("prepare st from 'select a from t where a in (?, ?)'")
+	tk.MustExec("set @a=1.0, @b=2.0")
+	tk.MustExec("execute st using @a, @b")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1105 skip plan-cache: '1.0' may be converted to INT"))
+	tk.MustExec("execute st using @a, @b")
+	tkProcess := tk.Session().ShowProcess()
+	ps := []*util.ProcessInfo{tkProcess}
+	tk.Session().SetSessionManager(&testkit.MockSessionManager{PS: ps})
+	tk.MustQuery(fmt.Sprintf("explain for connection %d", tkProcess.ID)).CheckAt([]int{0},
+		[][]interface{}{
+			{"IndexReader_6"},
+			{"└─IndexRangeScan_5"}, // range scan not full scan
+		})
+
+	tk.MustExec("set @a=1, @b=2")
+	tk.MustExec("execute st using @a, @b")
+	tk.MustQuery("show warnings").Check(testkit.Rows()) // no warning for INT values
+	tk.MustExec("execute st using @a, @b")
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1")) // cacheable for INT
+	tk.MustExec("execute st using @a, @b")
+	tk.MustQuery(fmt.Sprintf("explain for connection %d", tkProcess.ID)).CheckAt([]int{0},
+		[][]interface{}{
+			{"IndexReader_6"},
+			{"└─IndexRangeScan_5"}, // range scan not full scan
+		})
+}