planner: support pushing down predicates to memory tables in prepared mode

expression/expression.go

@@ -1574,6 +1574,8 @@ func Args2Expressions4Test(args ...interface{}) []Expression {
 			ft = types.NewFieldType(mysql.TypeDouble)
 		case types.KindString:
 			ft = types.NewFieldType(mysql.TypeVarString)
+		case types.KindMysqlTime:
+			ft = types.NewFieldType(mysql.TypeTimestamp)
 		default:
 			exprs[i] = nil
 			continue

planner/core/memtable_predicate_extractor.go

@@ -83,10 +83,14 @@ func (extractHelper) extractColInConsExpr(extractCols map[int64]*types.FieldName
 	results := make([]types.Datum, 0, len(args[1:]))
 	for _, arg := range args[1:] {
 		constant, ok := arg.(*expression.Constant)
-		if !ok || constant.DeferredExpr != nil || constant.ParamMarker != nil {
+		if !ok || constant.DeferredExpr != nil {
 			return "", nil
 		}
-		results = append(results, constant.Value)
+		v := constant.Value
+		if constant.ParamMarker != nil {
+			v = constant.ParamMarker.GetUserVar()
+		}
+		results = append(results, v)
 	}
 	return name.ColName.L, results
 }
@@ -117,10 +121,14 @@ func (extractHelper) extractColBinaryOpConsExpr(extractCols map[int64]*types.Fie
 	// SELECT * FROM t1 WHERE c='rhs'
 	// SELECT * FROM t1 WHERE 'lhs'=c
 	constant, ok := args[1-colIdx].(*expression.Constant)
-	if !ok || constant.DeferredExpr != nil || constant.ParamMarker != nil {
+	if !ok || constant.DeferredExpr != nil {
 		return "", nil
 	}
-	return name.ColName.L, []types.Datum{constant.Value}
+	v := constant.Value
+	if constant.ParamMarker != nil {
+		v = constant.ParamMarker.GetUserVar()
+	}
+	return name.ColName.L, []types.Datum{v}
 }
 
 // extract the OR expression, e.g:

planner/core/memtable_predicate_extractor_test.go

@@ -25,10 +25,14 @@ import (
 
 	"github.com/pingcap/tidb/domain"
 	"github.com/pingcap/tidb/errno"
+	"github.com/pingcap/tidb/expression"
 	"github.com/pingcap/tidb/parser"
+	"github.com/pingcap/tidb/parser/ast"
+	"github.com/pingcap/tidb/planner"
 	plannercore "github.com/pingcap/tidb/planner/core"
 	"github.com/pingcap/tidb/session"
 	"github.com/pingcap/tidb/testkit"
+	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/hint"
 	"github.com/pingcap/tidb/util/set"
 	"github.com/stretchr/testify/require"
@@ -1749,3 +1753,112 @@ PARTITION BY RANGE COLUMNS ( id ) (
 		require.Equal(t, ca.tableIDs, tableids)
 	}
 }
+
+func TestExtractorInPreparedStmt(t *testing.T) {
+	store, dom := testkit.CreateMockStoreAndDomain(t)
+	tk := testkit.NewTestKit(t, store)
+
+	var cases = []struct {
+		prepared string
+		userVars []interface{}
+		params   []interface{}
+		checker  func(extractor plannercore.MemTablePredicateExtractor)
+	}{
+		{
+			prepared: "select * from information_schema.TIKV_REGION_STATUS where table_id = ?",
+			userVars: []interface{}{1},
+			params:   []interface{}{1},
+			checker: func(extractor plannercore.MemTablePredicateExtractor) {
+				rse := extractor.(*plannercore.TiKVRegionStatusExtractor)
+				tableids := rse.GetTablesID()
+				slices.Sort(tableids)
+				require.Equal(t, []int64{1}, tableids)
+			},
+		},
+		{
+			prepared: "select * from information_schema.TIKV_REGION_STATUS where table_id = ? or table_id = ?",
+			userVars: []interface{}{1, 2},
+			params:   []interface{}{1, 2},
+			checker: func(extractor plannercore.MemTablePredicateExtractor) {
+				rse := extractor.(*plannercore.TiKVRegionStatusExtractor)
+				tableids := rse.GetTablesID()
+				slices.Sort(tableids)
+				require.Equal(t, []int64{1, 2}, tableids)
+			},
+		},
+		{
+			prepared: "select * from information_schema.TIKV_REGION_STATUS where table_id in (?,?)",
+			userVars: []interface{}{1, 2},
+			params:   []interface{}{1, 2},
+			checker: func(extractor plannercore.MemTablePredicateExtractor) {
+				rse := extractor.(*plannercore.TiKVRegionStatusExtractor)
+				tableids := rse.GetTablesID()
+				slices.Sort(tableids)
+				require.Equal(t, []int64{1, 2}, tableids)
+			},
+		},
+		{
+			prepared: "select * from information_schema.COLUMNS where table_name like ?",
+			userVars: []interface{}{`"a%"`},
+			params:   []interface{}{"a%"},
+			checker: func(extractor plannercore.MemTablePredicateExtractor) {
+				rse := extractor.(*plannercore.ColumnsTableExtractor)
+				require.EqualValues(t, []string{"a%"}, rse.TableNamePatterns)
+			},
+		},
+		{
+			prepared: "select * from information_schema.tidb_hot_regions_history where update_time>=?",
+			userVars: []interface{}{"cast('2019-10-10 10:10:10' as datetime)"},
+			params: []interface{}{func() types.Time {
+				tt, err := types.ParseTimestamp(tk.Session().GetSessionVars().StmtCtx, "2019-10-10 10:10:10")
+				require.NoError(t, err)
+				return tt
+			}()},
+			checker: func(extractor plannercore.MemTablePredicateExtractor) {
+				rse := extractor.(*plannercore.HotRegionsHistoryTableExtractor)
+				require.Equal(t, timestamp(t, "2019-10-10 10:10:10"), rse.StartTime)
+			},
+		},
+	}
+
+	// text protocol
+	parser := parser.New()
+	for _, ca := range cases {
+		tk.MustExec(fmt.Sprintf("prepare stmt from '%s'", ca.prepared))
+		setStmt := "set "
+		exec := "execute stmt using "
+		for i, uv := range ca.userVars {
+			name := fmt.Sprintf("@a%d", i)
+			setStmt += fmt.Sprintf("%s=%v", name, uv)
+			exec += name
+			if i != len(ca.userVars)-1 {
+				setStmt += ","
+				exec += ","
+			}
+		}
+		tk.MustExec(setStmt)
+		stmt, err := parser.ParseOneStmt(exec, "", "")
+		require.NoError(t, err)
+		plan, _, err := planner.OptimizeExecStmt(context.Background(), tk.Session(), stmt.(*ast.ExecuteStmt), dom.InfoSchema())
+		require.NoError(t, err)
+		extractor := plan.(*plannercore.Execute).Plan.(*plannercore.PhysicalMemTable).Extractor
+		ca.checker(extractor)
+	}
+
+	// binary protocol
+	for _, ca := range cases {
+		id, _, _, err := tk.Session().PrepareStmt(ca.prepared)
+		require.NoError(t, err)
+		prepStmt, err := tk.Session().GetSessionVars().GetPreparedStmtByID(id)
+		require.NoError(t, err)
+		params := expression.Args2Expressions4Test(ca.params...)
+		execStmt := &ast.ExecuteStmt{
+			BinaryArgs: params,
+			PrepStmt:   prepStmt,
+		}
+		plan, _, err := planner.OptimizeExecStmt(context.Background(), tk.Session(), execStmt, dom.InfoSchema())
+		require.NoError(t, err)
+		extractor := plan.(*plannercore.Execute).Plan.(*plannercore.PhysicalMemTable).Extractor
+		ca.checker(extractor)
+	}
+}