executor: fix wrong key range of index scan when filter is comparing …

…year column with NULL (pingcap#23079) (pingcap#23104)
wshwsh12 · Mar 18, 2021 · 11a9254 · 11a9254
1 parent aad2f72
commit 11a9254
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diff --git a/executor/executor_test.go b/executor/executor_test.go
@@ -1134,6 +1134,32 @@ func (s *testSuiteP1) TestIssue5055(c *C) {
 	result.Check(testkit.Rows("1 1"))
 }
 
+// issue-23038: wrong key range of index scan for year column
+func (s *testSuiteWithData) TestIndexScanWithYearCol(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test;")
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("create table t (c1 year(4), c2 int, key(c1));")
+	tk.MustExec("insert into t values(2001, 1);")
+
+	var input []string
+	var output []struct {
+		SQL  string
+		Plan []string
+		Res  []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 " + tt).Rows())
+			output[i].Res = s.testData.ConvertRowsToStrings(tk.MustQuery(tt).Sort().Rows())
+		})
+		tk.MustQuery("explain " + tt).Check(testkit.Rows(output[i].Plan...))
+		tk.MustQuery(tt).Sort().Check(testkit.Rows(output[i].Res...))
+	}
+}
+
 func (s *testSuiteP2) TestUnion(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")

diff --git a/executor/testdata/executor_suite_in.json b/executor/testdata/executor_suite_in.json
@@ -7,5 +7,17 @@
       "select * from t1 natural right join t2 order by a",
       "SELECT * FROM t1 NATURAL LEFT JOIN t2 WHERE not(t1.a <=> t2.a)"
     ]
+  },
+  {
+    "name": "TestIndexScanWithYearCol",
+    "cases": [
+      "select t1.c1, t2.c1 from t as t1 inner join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+      "select * from t as t1 inner join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+      "select count(*) from t as t1 inner join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+      "select t1.c1, t2.c1 from t as t1 left join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+      "select * from t as t1 left join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+      "select count(*) from t as t1 left join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+      "select * from t as t1 left join t as t2 on t1.c1 = t2.c1 where t1.c1 is not NULL"
+    ]
   }
 ]
diff --git a/executor/testdata/executor_suite_out.json b/executor/testdata/executor_suite_out.json
@@ -70,5 +70,89 @@
         ]
       }
     ]
+  },
+  {
+    "Name": "TestIndexScanWithYearCol",
+    "Cases": [
+      {
+        "SQL": "select t1.c1, t2.c1 from t as t1 inner join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+        "Plan": [
+            "MergeJoin_8 0.00 root  inner join, left key:test.t.c1, right key:test.t.c1",
+            "├─TableDual_24(Build) 0.00 root  rows:0",
+            "└─TableDual_23(Probe) 0.00 root  rows:0"
+        ],
+        "Res": [
+        ]
+      },
+      {
+        "SQL": "select * from t as t1 inner join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+        "Plan": [
+            "MergeJoin_8 0.00 root  inner join, left key:test.t.c1, right key:test.t.c1",
+            "├─TableDual_26(Build) 0.00 root  rows:0",
+            "└─TableDual_25(Probe) 0.00 root  rows:0"
+        ],
+        "Res": [
+        ]
+      },
+      {
+        "SQL": "select count(*) from t as t1 inner join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+        "Plan": [
+            "StreamAgg_10 1.00 root  funcs:count(1)->Column#7",
+            "└─MergeJoin_11 0.00 root  inner join, left key:test.t.c1, right key:test.t.c1",
+            "  ├─TableDual_27(Build) 0.00 root  rows:0",
+            "  └─TableDual_26(Probe) 0.00 root  rows:0"
+        ],
+        "Res": [
+          "0"
+        ]
+      },
+      {
+        "SQL": "select t1.c1, t2.c1 from t as t1 left join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+        "Plan": [
+            "MergeJoin_7 0.00 root  left outer join, left key:test.t.c1, right key:test.t.c1",
+            "├─TableDual_17(Build) 0.00 root  rows:0",
+            "└─TableDual_16(Probe) 0.00 root  rows:0"
+        ],
+        "Res": [
+        ]
+      },
+      {
+        "SQL": "select * from t as t1 left join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+        "Plan": [
+            "MergeJoin_7 0.00 root  left outer join, left key:test.t.c1, right key:test.t.c1",
+            "├─TableDual_18(Build) 0.00 root  rows:0",
+            "└─TableDual_17(Probe) 0.00 root  rows:0"
+        ],
+        "Res": [
+        ]
+      },
+      {
+        "SQL": "select count(*) from t as t1 left join t as t2 on t1.c1 = t2.c1 where t1.c1 != NULL",
+        "Plan": [
+            "StreamAgg_9 1.00 root  funcs:count(1)->Column#7",
+            "└─MergeJoin_10 0.00 root  left outer join, left key:test.t.c1, right key:test.t.c1",
+            "  ├─TableDual_20(Build) 0.00 root  rows:0",
+            "  └─TableDual_19(Probe) 0.00 root  rows:0"
+        ],
+        "Res": [
+          "0"
+        ]
+      },
+      {
+        "SQL": "select * from t as t1 left join t as t2 on t1.c1 = t2.c1 where t1.c1 is not NULL",
+        "Plan": [
+            "HashJoin_15 12487.50 root  left outer join, equal:[eq(test.t.c1, test.t.c1)]",
+            "├─TableReader_33(Build) 9990.00 root  data:Selection_32",
+            "│ └─Selection_32 9990.00 cop[tikv]  not(isnull(test.t.c1))",
+            "│   └─TableFullScan_31 10000.00 cop[tikv] table:t2 keep order:false, stats:pseudo",
+            "└─TableReader_27(Probe) 9990.00 root  data:Selection_26",
+            "  └─Selection_26 9990.00 cop[tikv]  not(isnull(test.t.c1))",
+            "    └─TableFullScan_25 10000.00 cop[tikv] table:t1 keep order:false, stats:pseudo"
+        ],
+        "Res": [
+          "2001 1 2001 1"
+        ]
+      }
+    ]
   }
 ]
diff --git a/types/datum.go b/types/datum.go
@@ -1427,6 +1427,10 @@ func (d *Datum) convertToMysqlFloatYear(sc *stmtctx.StatementContext, target *Fi
 		y = float64(d.GetMysqlTime().Year())
 	case KindMysqlDuration:
 		y = float64(time.Now().Year())
+	case KindNull:
+		// if datum is NULL, we should keep it as it is, instead of setting it to zero or any other value.
+		ret = *d
+		return ret, nil
 	default:
 		ret, err = d.convertToFloat(sc, NewFieldType(mysql.TypeDouble))
 		if err != nil {