feat: in sharding mode support show tables (#267)

* feat: in sharding mode support show tables

pkg/optimize/optimize_show_tables.go

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2022 CECTC, 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 optimize
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+
+	"github.com/cectc/dbpack/pkg/plan"
+	"github.com/cectc/dbpack/pkg/proto"
+	"github.com/cectc/dbpack/third_party/parser/ast"
+)
+
+func (o Optimizer) optimizeShowTables(ctx context.Context, stmt *ast.ShowStmt, args []interface{}) (proto.Plan, error) {
+	var logicTables []string
+	if stmt.Tp != ast.ShowTables {
+		return nil, errors.New("statement must be show tables stmt")
+	}
+
+	for logicTable := range o.topologies {
+		logicTables = append(logicTables, logicTable)
+	}
+
+	return &plan.ShowTablesPlan{
+		Stmt:        stmt,
+		Args:        args,
+		Executor:    o.executors[0],
+		LogicTables: logicTables,
+	}, nil
+}

pkg/optimize/optimizer.go

@@ -69,6 +69,8 @@ func (o Optimizer) Optimize(ctx context.Context, stmt ast.StmtNode, args ...inte
 		switch t.Tp {
 		case ast.ShowTableStatus:
 			return o.optimizeShowTableStatus(ctx, t, args)
+		case ast.ShowTables:
+			return o.optimizeShowTables(ctx, t, args)
 		case ast.ShowColumns, ast.ShowIndex:
 			return o.optimizeShowTableMeta(ctx, t, args)
 		}

pkg/plan/show_tables.go

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2022 CECTC, 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 plan
+
+import (
+	"context"
+	"regexp"
+	"strings"
+
+	"github.com/pkg/errors"
+
+	"github.com/cectc/dbpack/pkg/constant"
+	"github.com/cectc/dbpack/pkg/mysql"
+	"github.com/cectc/dbpack/pkg/proto"
+	"github.com/cectc/dbpack/third_party/parser/ast"
+	"github.com/cectc/dbpack/third_party/parser/format"
+)
+
+const (
+	tableNameRegex = `^(\w+)_(\d+)$`
+)
+
+var (
+	tableNameRegexp = regexp.MustCompile(tableNameRegex)
+)
+
+type ShowTablesPlan struct {
+	Stmt        *ast.ShowStmt
+	Args        []interface{}
+	Executor    proto.DBGroupExecutor
+	LogicTables []string
+}
+
+func (p *ShowTablesPlan) Execute(ctx context.Context, _ ...*ast.TableOptimizerHint) (proto.Result, uint16, error) {
+	var (
+		sb     strings.Builder
+		sql    string
+		result proto.Result
+		warns  uint16
+		err    error
+	)
+	restoreCtx := format.NewRestoreCtx(constant.DBPackRestoreFormat, &sb)
+	if err = p.Stmt.Restore(restoreCtx); err != nil {
+		return nil, 0, errors.WithStack(err)
+	}
+	sql = sb.String()
+
+	result, warns, err = p.Executor.Query(ctx, sql)
+	if err != nil {
+		return nil, 0, err
+	}
+	mysqlResult := result.(*mysql.Result)
+	rows := make([]proto.Row, 0)
+	rowMap := make(map[string]struct{})
+	for _, row := range mysqlResult.Rows {
+		if _, err := row.Decode(); err != nil {
+			return nil, 0, err
+		}
+		textRow := row.(*mysql.TextRow)
+		table, filtered := filterTable(string(textRow.Values[0].Val.([]byte)), p.LogicTables)
+		if filtered {
+			textRow.Values[0].Val = []byte(table)
+		}
+		if _, exist := rowMap[table]; !exist {
+			rows = append(rows, textRow)
+			rowMap[table] = struct{}{}
+		}
+	}
+	return &mysql.Result{
+		Fields:       mysqlResult.Fields,
+		AffectedRows: mysqlResult.AffectedRows,
+		InsertId:     mysqlResult.InsertId,
+		Rows:         rows,
+	}, warns, nil
+}
+
+// filterTable return table, filtered
+func filterTable(table string, logicTables []string) (string, bool) {
+	for _, logicTable := range logicTables {
+		if tableNameRegexp.MatchString(table) {
+			if strings.Contains(table, logicTable) {
+				return logicTable, true
+			}
+		}
+	}
+	return table, false
+}

test/shd/sharding_test.go

@@ -277,6 +277,20 @@ func (suite *_ShardingSuite) TestShowTableStatus() {
 	}
 }
 
+func (suite *_ShardingSuite) TestShowTables() {
+	rows, err := suite.db.Query("SHOW TABLES")
+	if suite.NoErrorf(err, "show tables error: %v", err) {
+		var (
+			table string
+		)
+		for rows.Next() {
+			err := rows.Scan(&table)
+			suite.NoError(err)
+			suite.T().Logf("%s", table)
+		}
+	}
+}
+
 func (suite *_ShardingSuite) TestShowTableMeta() {
 	rows, err := suite.db.Query("SHOW COLUMNS FROM city")
 	if suite.NoErrorf(err, "show columns error: %v", err) {