Optimizer: add test cases for predicate simplifications (#41117)

ref #40221

planner/core/BUILD.bazel

@@ -199,6 +199,7 @@ go_test(
         "plan_to_pb_test.go",
         "planbuilder_test.go",
         "point_get_plan_test.go",
+        "predicate_simplification_test.go",
         "prepare_test.go",
         "preprocess_test.go",
         "rule_inject_extra_projection_test.go",

planner/core/predicate_simplification_test.go

@@ -0,0 +1,63 @@
+// Copyright 2023 PingCAP, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package core_test
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/pingcap/tidb/infoschema"
+	"github.com/pingcap/tidb/parser"
+	"github.com/pingcap/tidb/parser/model"
+	"github.com/pingcap/tidb/planner"
+	"github.com/pingcap/tidb/planner/core"
+	"github.com/pingcap/tidb/sessiontxn"
+	"github.com/pingcap/tidb/testkit"
+	"github.com/pingcap/tidb/testkit/testdata"
+	"github.com/stretchr/testify/require"
+)
+
+// Test redundant conditions in single table and join predicates.
+func TestRemoveRedundantPredicates(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("set tidb_cost_model_version=2")
+	tk.MustExec("set tidb_opt_limit_push_down_threshold=0")
+	var input []string
+	var output []struct {
+		SQL  string
+		Best string
+	}
+	planSuiteData := core.GetPlanSuiteData()
+	planSuiteData.LoadTestCases(t, &input, &output)
+	p := parser.New()
+	is := infoschema.MockInfoSchema([]*model.TableInfo{core.MockSignedTable(), core.MockUnsignedTable()})
+	for i, tt := range input {
+		comment := fmt.Sprintf("case: %v, sql: %s", i, tt)
+		stmt, err := p.ParseOneStmt(tt, "", "")
+		require.NoError(t, err, comment)
+		require.NoError(t, sessiontxn.NewTxn(context.Background(), tk.Session()))
+		p, _, err := planner.Optimize(context.TODO(), tk.Session(), stmt, is)
+		require.NoError(t, err)
+		testdata.OnRecord(func() {
+			output[i].SQL = tt
+			output[i].Best = core.ToString(p)
+		})
+		require.Equal(t, output[i].Best, core.ToString(p), comment)
+	}
+}

planner/core/testdata/plan_suite_in.json

@@ -1194,5 +1194,21 @@
         "select  /*+ agg_to_cop() hash_agg() */  count(1) from tbl_15 ;",
         "select  /*+ agg_to_cop() stream_agg() */  avg(   tbl_16.col_100 ) as r0 from tbl_16 where tbl_16.col_100 in ( 10672141 ) or tbl_16.col_104 in ( 'yfEG1t!*b' ,'C1*bqx_qyO' ,'vQ^yUpKHr&j#~' ) group by tbl_16.col_100  order by r0 limit 20 ;"
     ]
+  },
+  {
+    "name": "TestRemoveRedundantPredicates",
+    "cases":[
+      "select f from t use index() where f = 1 and f = 1 -- simple redundancy of exact condition",
+      "select f from t use index() where f = 1 and f = 2 -- unsatisfiable condition",
+      "select f from t use index() where f = 1 and f in (1,2,3)  -- intersection of in and =",
+      "select f from t use index() where f = 1 and f <> 1  -- intersection of = and <>",
+      "select f from t use index() where f not in (1,2,3) and f = 3 -- intersection of not in list and =",
+      "select f from t use index() where f <> 3 and f <> 3 -- intersection of two not in values.",
+      "select t1.f /* merge_join(t1, t2) */ from t t1, t t2 where t1.a=t2.a and t1.a=t2.a -- exact redundancy in joins",
+      "select f from t use index() where f in (1,2,3) and f <> 2 -- intersection of in and <>. Not done yet see issue 39676",
+      "select f from t use index() where f in (1,2,3) and f in (3,4,5) -- intersection of two in. Not done yet",
+      "select f from t use index() where f not in (1,2,3) and f not in (3,4,5) -- intersection of two not in. Not done yet",
+      "select f from t use index() where f not in (1,2,3) and f in (1,2,3) -- intersection of in and not in. Not done yet"
+    ]
   }
 ]

planner/core/testdata/plan_suite_out.json

@@ -7600,5 +7600,54 @@
         "Warning": null
       }
     ]
+  },
+  {
+    "Name": "TestRemoveRedundantPredicates",
+    "Cases": [
+      {
+        "SQL": "select f from t use index() where f = 1 and f = 1 -- simple redundancy of exact condition",
+        "Best": "TableReader(Table(t)->Sel([eq(test.t.f, 1)]))"
+      },
+      {
+        "SQL": "select f from t use index() where f = 1 and f = 2 -- unsatisfiable condition",
+        "Best": "Dual"
+      },
+      {
+        "SQL": "select f from t use index() where f = 1 and f in (1,2,3)  -- intersection of in and =",
+        "Best": "TableReader(Table(t)->Sel([eq(test.t.f, 1)]))"
+      },
+      {
+        "SQL": "select f from t use index() where f = 1 and f <> 1  -- intersection of = and <>",
+        "Best": "Dual"
+      },
+      {
+        "SQL": "select f from t use index() where f not in (1,2,3) and f = 3 -- intersection of not in list and =",
+        "Best": "Dual"
+      },
+      {
+        "SQL": "select f from t use index() where f <> 3 and f <> 3 -- intersection of two not in values.",
+        "Best": "TableReader(Table(t)->Sel([ne(test.t.f, 3)]))"
+      },
+      {
+        "SQL": "select t1.f /* merge_join(t1, t2) */ from t t1, t t2 where t1.a=t2.a and t1.a=t2.a -- exact redundancy in joins",
+        "Best": "MergeInnerJoin{TableReader(Table(t))->TableReader(Table(t))}(test.t.a,test.t.a)"
+      },
+      {
+        "SQL": "select f from t use index() where f in (1,2,3) and f <> 2 -- intersection of in and <>. Not done yet see issue 39676",
+        "Best": "TableReader(Table(t)->Sel([in(test.t.f, 1, 2, 3) ne(test.t.f, 2)]))"
+      },
+      {
+        "SQL": "select f from t use index() where f in (1,2,3) and f in (3,4,5) -- intersection of two in. Not done yet",
+        "Best": "TableReader(Table(t)->Sel([in(test.t.f, 1, 2, 3) in(test.t.f, 3, 4, 5)]))"
+      },
+      {
+        "SQL": "select f from t use index() where f not in (1,2,3) and f not in (3,4,5) -- intersection of two not in. Not done yet",
+        "Best": "TableReader(Table(t)->Sel([not(in(test.t.f, 1, 2, 3)) not(in(test.t.f, 3, 4, 5))]))"
+      },
+      {
+        "SQL": "select f from t use index() where f not in (1,2,3) and f in (1,2,3) -- intersection of in and not in. Not done yet",
+        "Best": "TableReader(Table(t)->Sel([not(in(test.t.f, 1, 2, 3)) in(test.t.f, 1, 2, 3)]))"
+      }
+    ]
   }
 ]