feat: support show status (#309)

pkg/executor/redirect.go

@@ -259,7 +259,7 @@ func (executor *RedirectExecutor) ExecutorComQuery(ctx *proto.Context) (proto.Re
 	case *ast.ShowStmt:
 		allowSchemaless := func(stmt *ast.ShowStmt) bool {
 			switch stmt.Tp {
-			case ast.ShowDatabases, ast.ShowVariables, ast.ShowTopology:
+			case ast.ShowDatabases, ast.ShowVariables, ast.ShowTopology, ast.ShowStatus:
 				return true
 			default:
 				return false

pkg/runtime/ast/ast.go

@@ -671,6 +671,12 @@ func (cc *convCtx) convShowStmt(node *ast.ShowStmt) Statement {
 			ret.like.String = like
 		}
 		return ret
+	case ast.ShowStatus:
+		ret := &ShowStatus{
+			baseShow: toBaseShow(),
+			global:   node.GlobalScope,
+		}
+		return ret
 	default:
 		panic(fmt.Sprintf("unimplement: show type %v!", node.Tp))
 	}

pkg/runtime/ast/proto.go

@@ -45,6 +45,7 @@ const (
 	SQLTypeUnion                  // UNION
 	SQLTypeDropTrigger            // DROP TRIGGER
 	SQLTypeCreateIndex            // CREATE INDEX
+	SQLTypeShowStatus             // SHOW STATUS
 )
 
 type RestoreFlag uint32
@@ -80,6 +81,7 @@ var _sqlTypeNames = [...]string{
 	SQLTypeUnion:          "UNION",
 	SQLTypeDropTrigger:    "DROP TRIGGER",
 	SQLTypeCreateIndex:    "CREATE INDEX",
+	SQLTypeShowStatus:     "SHOW STATUS",
 }
 
 // SQLType represents the type of SQL.

pkg/runtime/ast/show.go

@@ -402,3 +402,34 @@ func (s *ShowVariables) CntParams() int {
 func (s *ShowVariables) Mode() SQLType {
 	return SQLTypeShowVariables
 }
+
+type ShowStatus struct {
+	*baseShow
+	flag   showColumnsFlag
+	global bool
+}
+
+func (s *ShowStatus) Validate() error {
+	return nil
+}
+
+func (s *ShowStatus) Restore(flag RestoreFlag, sb *strings.Builder, args *[]int) error {
+	sb.WriteString("SHOW ")
+
+	if s.global {
+		sb.WriteString(" GLOBAL ")
+	} else {
+		sb.WriteString(" SESSION ")
+	}
+	sb.WriteString(" STATUS ")
+
+	if err := s.baseShow.Restore(flag, sb, args); err != nil {
+		return errors.WithStack(err)
+	}
+
+	return nil
+}
+
+func (s *ShowStatus) Mode() SQLType {
+	return SQLTypeShowStatus
+}

pkg/runtime/optimize/dal/show_status.go

@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 dal
+
+import (
+	"context"
+)
+
+import (
+	"github.com/arana-db/arana/pkg/proto"
+	"github.com/arana-db/arana/pkg/runtime/ast"
+	"github.com/arana-db/arana/pkg/runtime/optimize"
+	"github.com/arana-db/arana/pkg/runtime/plan/dal"
+)
+
+func init() {
+	optimize.Register(ast.SQLTypeShowStatus, optimizeShowStatus)
+}
+
+func optimizeShowStatus(_ context.Context, o *optimize.Optimizer) (proto.Plan, error) {
+	stmt := o.Stmt.(*ast.ShowStatus)
+
+	ret := dal.NewShowStatusPlan(stmt)
+	ret.BindArgs(o.Args)
+
+	return ret, nil
+}

pkg/runtime/plan/dal/show_status.go

@@ -0,0 +1,70 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 dal
+
+import (
+	"context"
+	"strings"
+)
+
+import (
+	"github.com/pkg/errors"
+)
+
+import (
+	"github.com/arana-db/arana/pkg/proto"
+	"github.com/arana-db/arana/pkg/runtime/ast"
+	"github.com/arana-db/arana/pkg/runtime/plan"
+)
+
+var _ proto.Plan = (*ShowOpenTablesPlan)(nil)
+
+type ShowStatusPlan struct {
+	plan.BasePlan
+	Database string
+	stmt     *ast.ShowStatus
+}
+
+func NewShowStatusPlan(stmt *ast.ShowStatus) *ShowStatusPlan {
+	return &ShowStatusPlan{stmt: stmt}
+}
+
+func (s *ShowStatusPlan) Type() proto.PlanType {
+	return proto.PlanTypeQuery
+}
+
+func (s *ShowStatusPlan) ExecIn(ctx context.Context, vConn proto.VConn) (proto.Result, error) {
+	var (
+		sb   strings.Builder
+		args []int
+	)
+	ctx, span := plan.Tracer.Start(ctx, "ShowStatusPlan.ExecIn")
+	defer span.End()
+
+	if err := s.stmt.Restore(ast.RestoreDefault, &sb, &args); err != nil {
+		return nil, errors.Wrap(err, "failed to execute SHOW STATUS statement")
+	}
+
+	ret, err := vConn.Query(ctx, "", sb.String(), s.ToArgs(args)...)
+	if err != nil {
+		return nil, err
+	}
+
+	return ret, nil
+}

test/integration_test.go

@@ -606,3 +606,36 @@ func (s *IntegrationSuite) TestHints() {
 	}
 
 }
+
+func (s *IntegrationSuite) TestShowStatus() {
+	var (
+		db = s.DB()
+		t  = s.T()
+	)
+
+	type tt struct {
+		sql     string
+		expectF func(t *testing.T, data [][]string) bool
+	}
+
+	for _, it := range []tt{
+		{"SHOW STATUS", func(t *testing.T, data [][]string) bool {
+			t.Logf("%+v", data)
+			return len(data) > 0
+		}},
+		{"SHOW STATUS LIKE 'Key%';", func(t *testing.T, data [][]string) bool {
+			t.Logf("%+v", data)
+			return len(data) >= 5
+		}},
+	} {
+		t.Run(it.sql, func(t *testing.T) {
+			// show table status
+			rows, err := db.Query(it.sql)
+			assert.NoError(t, err, "should query status successfully")
+			defer rows.Close()
+			data, _ := utils.PrintTable(rows)
+			assert.True(t, it.expectF(t, data))
+		})
+	}
+
+}