planner: add unit test for tidb_opt_prefer_range_scan variable

planner/core/physical_plan_test.go

@@ -1623,3 +1623,91 @@ func (s *testPlanSuite) TestNthPlanHintWithExplain(c *C) {
 	// hold in the future, you may need to modify this.
 	tk.MustQuery("explain select * from test.tt where a=1 and b=1").Check(testkit.Rows(output[1].Plan...))
 }
+
+func (s *testPlanSuite) TestPreferRangeScanOff(c *C) {
+	var (
+		input  []string
+		output []struct {
+			SQL    string
+			Plan   []string
+			Result []string
+		}
+	)
+	s.testData.GetTestCases(c, &input, &output)
+	store, dom, err := newStoreWithBootstrap()
+	c.Assert(err, IsNil)
+	defer func() {
+		dom.Close()
+		store.Close()
+	}()
+	tk := testkit.NewTestKit(c, store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists test;")
+	tk.MustExec("create table test(`id` int(10) NOT NULL AUTO_INCREMENT,`name` varchar(50) NOT NULL DEFAULT 'tidb',`age` int(11) NOT NULL,`addr` varchar(50) DEFAULT 'The ocean of stars',PRIMARY KEY (`id`),KEY `idx_age` (`age`))")
+	tk.MustExec("insert into test(age) values(5);")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("analyze table test;")
+	tk.MustExec(fmt.Sprintf("set session tidb_opt_prefer_range_scan = %v", 0))
+
+	for i, ts := range input {
+		s.testData.OnRecord(func() {
+			output[i].SQL = ts
+			output[i].Plan = s.testData.ConvertRowsToStrings(tk.MustQuery("explain " + ts).Rows())
+		})
+		tk.MustQuery("explain " + ts).Check(testkit.Rows(output[i].Plan...))
+	}
+}
+
+func (s *testPlanSuite) TestPreferRangeScanOn(c *C) {
+	var (
+		input  []string
+		output []struct {
+			SQL    string
+			Plan   []string
+			Result []string
+		}
+	)
+	s.testData.GetTestCases(c, &input, &output)
+	store, dom, err := newStoreWithBootstrap()
+	c.Assert(err, IsNil)
+	defer func() {
+		dom.Close()
+		store.Close()
+	}()
+	tk := testkit.NewTestKit(c, store)
+	tk.MustExec("use test")
+	tk.MustExec("drop table if exists test;")
+	tk.MustExec("create table test(`id` int(10) NOT NULL AUTO_INCREMENT,`name` varchar(50) NOT NULL DEFAULT 'tidb',`age` int(11) NOT NULL,`addr` varchar(50) DEFAULT 'The ocean of stars',PRIMARY KEY (`id`),KEY `idx_age` (`age`))")
+	tk.MustExec("insert into test(age) values(5);")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("insert into test(name,age,addr) select name,age,addr from test;")
+	tk.MustExec("analyze table test;")
+	tk.MustExec(fmt.Sprintf("set session tidb_opt_prefer_range_scan = %v", 1))
+
+	for i, ts := range input {
+		s.testData.OnRecord(func() {
+			output[i].SQL = ts
+			output[i].Plan = s.testData.ConvertRowsToStrings(tk.MustQuery("explain " + ts).Rows())
+		})
+		tk.MustQuery("explain " + ts).Check(testkit.Rows(output[i].Plan...))
+	}
+}

planner/core/testdata/plan_suite_in.json

@@ -662,5 +662,17 @@
       "select a from t2 where t2.a < (select t1.a from t1 where t1.b = t2.b and t1.a is null);",
       "select a from t2 where t2.a < (select t3.a from t3 where t3.a = t2.a);"
     ]
+  },
+  {
+    "name": "TestPreferRangeScanOff",
+    "cases": [
+      "select * from test where age=5;"
+    ]
+  },
+  {
+    "name": "TestPreferRangeScanOn",
+    "cases": [
+      "select * from test where age=5;"
+    ]
   }
 ]

planner/core/testdata/plan_suite_out.json

@@ -2219,5 +2219,31 @@
         ]
       }
     ]
+  },
+  {
+    "Name": "TestPreferRangeScanOff",
+    "Cases": [
+      {
+        "SQL": "select * from test where age=5;",
+        "Plan": [
+          "TableReader_7 2048.00 root  data:Selection_6",
+          "└─Selection_6 2048.00 cop[tikv]  eq(test.test.age, 5)",
+          "  └─TableFullScan_5 2048.00 cop[tikv] table:test keep order:false"
+        ]
+      }
+    ]
+  },
+  {
+    "Name": "TestPreferRangeScanOn",
+    "Cases": [
+      {
+        "SQL": "select * from test where age=5;",
+        "Plan": [
+          "IndexLookUp_7 2048.00 root  ",
+          "├─IndexRangeScan_5(Build) 2048.00 cop[tikv] table:test, index:idx_age(age) range:[5,5], keep order:false",
+          "└─TableRowIDScan_6(Probe) 2048.00 cop[tikv] table:test keep order:false"
+        ]
+      }
+    ]
   }
 ]