vitess.io/vitess@v0.16.2/go/vt/vtgate/planbuilder/single_sharded_shortcut.go (about)

     1  /*
     2  Copyright 2022 The Vitess Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package planbuilder
    18  
    19  import (
    20  	"sort"
    21  	"strings"
    22  
    23  	"vitess.io/vitess/go/vt/vtgate/planbuilder/operators"
    24  	"vitess.io/vitess/go/vt/vtgate/planbuilder/plancontext"
    25  
    26  	"vitess.io/vitess/go/vt/sqlparser"
    27  	"vitess.io/vitess/go/vt/vtgate/engine"
    28  	"vitess.io/vitess/go/vt/vtgate/semantics"
    29  	"vitess.io/vitess/go/vt/vtgate/vindexes"
    30  )
    31  
    32  func unshardedShortcut(ctx *plancontext.PlanningContext, stmt sqlparser.SelectStatement, ks *vindexes.Keyspace) (logicalPlan, []string, error) {
    33  	// this method is used when the query we are handling has all tables in the same unsharded keyspace
    34  	sqlparser.SafeRewrite(stmt, nil, func(cursor *sqlparser.Cursor) bool {
    35  		switch node := cursor.Node().(type) {
    36  		case sqlparser.SelectExpr:
    37  			removeKeyspaceFromSelectExpr(node)
    38  		case sqlparser.TableName:
    39  			cursor.Replace(sqlparser.TableName{
    40  				Name: node.Name,
    41  			})
    42  		}
    43  		return true
    44  	})
    45  
    46  	tableNames, err := getTableNames(ctx.SemTable)
    47  	if err != nil {
    48  		return nil, nil, err
    49  	}
    50  	plan := &routeGen4{
    51  		eroute: &engine.Route{
    52  			RoutingParameters: &engine.RoutingParameters{
    53  				Opcode:   engine.Unsharded,
    54  				Keyspace: ks,
    55  			},
    56  			TableName: strings.Join(escapedTableNames(tableNames), ", "),
    57  		},
    58  		Select: stmt,
    59  	}
    60  
    61  	if err := plan.WireupGen4(ctx); err != nil {
    62  		return nil, nil, err
    63  	}
    64  	return plan, operators.QualifiedTableNames(ks, tableNames), nil
    65  }
    66  
    67  func escapedTableNames(tableNames []sqlparser.TableName) []string {
    68  	escaped := make([]string, len(tableNames))
    69  	for i, tableName := range tableNames {
    70  		escaped[i] = sqlparser.String(tableName)
    71  	}
    72  	return escaped
    73  }
    74  
    75  func getTableNames(semTable *semantics.SemTable) ([]sqlparser.TableName, error) {
    76  	tableNameMap := make(map[string]sqlparser.TableName)
    77  
    78  	for _, tableInfo := range semTable.Tables {
    79  		tblObj := tableInfo.GetVindexTable()
    80  		if tblObj == nil {
    81  			// probably a derived table
    82  			continue
    83  		}
    84  		if tableInfo.IsInfSchema() {
    85  			tableNameMap["tableName"] = sqlparser.TableName{
    86  				Name: sqlparser.NewIdentifierCS("tableName"),
    87  			}
    88  		} else {
    89  			tableNameMap[sqlparser.String(tblObj.Name)] = sqlparser.TableName{
    90  				Name: tblObj.Name,
    91  			}
    92  		}
    93  	}
    94  	var keys []string
    95  	for k := range tableNameMap {
    96  		keys = append(keys, k)
    97  	}
    98  	sort.Strings(keys)
    99  	var tableNames []sqlparser.TableName
   100  	for _, k := range keys {
   101  		tableNames = append(tableNames, tableNameMap[k])
   102  	}
   103  	return tableNames, nil
   104  }