planbuilder

Documentation

Overview

Package planbuilder allows you to build execution plans that describe how to fulfill a query that may span multiple keyspaces or shards. The main entry points for this package are Build and BuildFromStmt.

Index

• Constants
• Variables
• func BuildColName(rcs []*resultColumn, index int) (*sqlparser.ColName, error)
• func BuildFromStmt(query string, stmt sqlparser.Statement, reservedVars *sqlparser.ReservedVars, ...) (*engine.Plan, error)
• func GetReturnType(input sqlparser.Expr) (querypb.Type, error)
• func ResultFromNumber(rcs []*resultColumn, val *sqlparser.Literal) (int, error)
• func TestBuilder(query string, vschema ContextVSchema) (*engine.Plan, error)
• type ContextVSchema
• type PlannerVersion
• type UnsupportedSupplyWeightString
  • func (err UnsupportedSupplyWeightString) Error() string

Constants

const (
	// V3 is also the default planner
	V3 = querypb.ExecuteOptions_V3
	// Gen4 uses the default Gen4 planner, which is the greedy planner
	Gen4 = querypb.ExecuteOptions_Gen4
	// Gen4GreedyOnly uses only the faster greedy planner
	Gen4GreedyOnly = querypb.ExecuteOptions_Gen4Greedy
	// Gen4Left2Right tries to emulate the V3 planner by only joining plans in the order they are listed in the FROM-clause
	Gen4Left2Right = querypb.ExecuteOptions_Gen4Left2Right
	// Gen4WithFallback first attempts to use the Gen4 planner, and if that fails, uses the V3 planner instead
	Gen4WithFallback = querypb.ExecuteOptions_Gen4WithFallback
)

const (
	ViewDifferentKeyspace string = "Select query does not belong to the same keyspace as the view statement"
	ViewComplex           string = "Complex select queries are not supported in create or alter view statements"
	DifferentDestinations string = "Tables or Views specified in the query do not belong to the same destination"
)

Error messages for CreateView queries

Variables

var ErrPlanNotSupported = errors.New("plan building not supported")

ErrPlanNotSupported is an error for plan building not supported

Functions

func BuildColName

func BuildColName(rcs []*resultColumn, index int) (*sqlparser.ColName, error)

BuildColName builds a *sqlparser.ColName for the resultColumn specified by the index. The built ColName will correctly reference the resultColumn it was built from.

func BuildFromStmt

func BuildFromStmt(query string, stmt sqlparser.Statement, reservedVars *sqlparser.ReservedVars, vschema ContextVSchema, bindVarNeeds *sqlparser.BindVarNeeds, enableOnlineDDL, enableDirectDDL bool) (*engine.Plan, error)

BuildFromStmt builds a plan based on the AST provided.

func GetReturnType

func GetReturnType(input sqlparser.Expr) (querypb.Type, error)

GetReturnType returns the type of the select expression that MySQL will return

func ResultFromNumber

func ResultFromNumber(rcs []*resultColumn, val *sqlparser.Literal) (int, error)

ResultFromNumber returns the result column index based on the column order expression.

func TestBuilder

func TestBuilder(query string, vschema ContextVSchema) (*engine.Plan, error)

TestBuilder builds a plan for a query based on the specified vschema. This method is only used from tests

Types

type ContextVSchema

type ContextVSchema interface {
	FindTable(tablename sqlparser.TableName) (*vindexes.Table, string, topodatapb.TabletType, key.Destination, error)
	FindTableOrVindex(tablename sqlparser.TableName) (*vindexes.Table, vindexes.Vindex, string, topodatapb.TabletType, key.Destination, error)
	DefaultKeyspace() (*vindexes.Keyspace, error)
	TargetString() string
	Destination() key.Destination
	TabletType() topodatapb.TabletType
	TargetDestination(qualifier string) (key.Destination, *vindexes.Keyspace, topodatapb.TabletType, error)
	AnyKeyspace() (*vindexes.Keyspace, error)
	FirstSortedKeyspace() (*vindexes.Keyspace, error)
	SysVarSetEnabled() bool
	KeyspaceExists(keyspace string) bool
	AllKeyspace() ([]*vindexes.Keyspace, error)
	GetSemTable() *semantics.SemTable
	Planner() PlannerVersion

	// ErrorIfShardedF will return an error if the keyspace is sharded,
	// and produce a warning if the vtgate if configured to do so
	ErrorIfShardedF(keyspace *vindexes.Keyspace, warn, errFmt string, params ...interface{}) error

	// WarnUnshardedOnly is used when a feature is only supported in unsharded mode.
	// This will let the user know that they are using something
	// that could become a problem if they move to a sharded keyspace
	WarnUnshardedOnly(format string, params ...interface{})

	// ForeignKeyMode returns the foreign_key flag value
	ForeignKeyMode() string
}

ContextVSchema defines the interface for this package to fetch info about tables.

type PlannerVersion

type PlannerVersion = querypb.ExecuteOptions_PlannerVersion

PlannerVersion is an alias here to make the code more readable

type UnsupportedSupplyWeightString

type UnsupportedSupplyWeightString struct {
	Type string
}

UnsupportedSupplyWeightString represents the error where the supplying a weight string is not supported

func (UnsupportedSupplyWeightString) Error

func (err UnsupportedSupplyWeightString) Error() string

Error function implements the error interface