hint

Documentation

Index

• func BindHint(stmt ast.StmtNode, hintsSet *HintsSet) ast.StmtNode
• func CheckBindingFromHistoryBindable(node ast.Node, hintStr string) error
• func ExtractTableHintsFromStmtNode(node ast.Node, sctx sessionctx.Context) []*ast.TableOptimizerHint
• func GenerateQBName(nodeType NodeType, blockOffset int) (model.CIStr, error)
• func RestoreIndexHint(hint *ast.IndexHint) (string, error)
• func RestoreOptimizerHints(hints []*ast.TableOptimizerHint) string
• func RestoreTableOptimizerHint(hint *ast.TableOptimizerHint) string
• type BlockHintProcessor
  • func (p *BlockHintProcessor) Enter(in ast.Node) (ast.Node, bool)
  • func (p *BlockHintProcessor) GetCurrentStmtHints(hints []*ast.TableOptimizerHint, currentOffset int) []*ast.TableOptimizerHint
  • func (p *BlockHintProcessor) GetHintOffset(qbName model.CIStr, currentOffset int) int
  • func (p *BlockHintProcessor) HandleUnusedViewHints()
  • func (*BlockHintProcessor) Leave(in ast.Node) (ast.Node, bool)
  • func (p *BlockHintProcessor) MaxSelectStmtOffset() int
• type HintsSet
  • func CollectHint(in ast.StmtNode) *HintsSet
  • func ParseHintsSet(p *parser.Parser, sql, charset, collation, db string) (*HintsSet, ast.StmtNode, []error, error)
  • func (hs *HintsSet) ContainTableHint(hint string) bool
  • func (hs *HintsSet) GetFirstTableHints() []*ast.TableOptimizerHint
  • func (hs *HintsSet) Restore() (string, error)
• type NodeType

Functions

func BindHint

func BindHint(stmt ast.StmtNode, hintsSet *HintsSet) ast.StmtNode

BindHint will add hints for stmt according to the hints in `hintsSet`.

func CheckBindingFromHistoryBindable

func CheckBindingFromHistoryBindable(node ast.Node, hintStr string) error

CheckBindingFromHistoryBindable checks whether the ast and hint string from history is bindable. Not support: 1. query use tiFlash engine 2. query with sub query 3. query with more than 2 table join

func ExtractTableHintsFromStmtNode

func ExtractTableHintsFromStmtNode(node ast.Node, sctx sessionctx.Context) []*ast.TableOptimizerHint

ExtractTableHintsFromStmtNode extracts table hints from this node.

func GenerateQBName

func GenerateQBName(nodeType NodeType, blockOffset int) (model.CIStr, error)

GenerateQBName builds QBName from offset.

func RestoreIndexHint

func RestoreIndexHint(hint *ast.IndexHint) (string, error)

RestoreIndexHint returns string format of IndexHint.

func RestoreOptimizerHints

func RestoreOptimizerHints(hints []*ast.TableOptimizerHint) string

RestoreOptimizerHints restores these hints.

func RestoreTableOptimizerHint

func RestoreTableOptimizerHint(hint *ast.TableOptimizerHint) string

RestoreTableOptimizerHint returns string format of TableOptimizerHint.

Types

type BlockHintProcessor

type BlockHintProcessor struct {
	QbNameMap map[string]int                    // Map from query block name to select stmt offset.
	QbHints   map[int][]*ast.TableOptimizerHint // Group all hints at same query block.

	// Used for the view's hint
	QbNameMap4View  map[string][]ast.HintTable           // Map from view's query block name to view's table list.
	QbHints4View    map[string][]*ast.TableOptimizerHint // Group all hints at same query block for view hints.
	QbNameUsed4View map[string]struct{}                  // Store all the qb_name hints which are used for view

	Ctx sessionctx.Context
	// contains filtered or unexported fields
}

BlockHintProcessor processes hints at different level of sql statement.

func (*BlockHintProcessor) Enter

func (p *BlockHintProcessor) Enter(in ast.Node) (ast.Node, bool)

Enter implements Visitor interface.

func (*BlockHintProcessor) GetCurrentStmtHints

func (p *BlockHintProcessor) GetCurrentStmtHints(hints []*ast.TableOptimizerHint, currentOffset int) []*ast.TableOptimizerHint

GetCurrentStmtHints extracts all hints that take effects at current stmt.

func (*BlockHintProcessor) GetHintOffset

func (p *BlockHintProcessor) GetHintOffset(qbName model.CIStr, currentOffset int) int

GetHintOffset gets the offset of stmt that the hints take effects.

func (*BlockHintProcessor) HandleUnusedViewHints

func (p *BlockHintProcessor) HandleUnusedViewHints()

HandleUnusedViewHints handle the unused view hints.

func (*BlockHintProcessor) Leave

func (*BlockHintProcessor) Leave(in ast.Node) (ast.Node, bool)

Leave implements Visitor interface.

func (*BlockHintProcessor) MaxSelectStmtOffset

func (p *BlockHintProcessor) MaxSelectStmtOffset() int

MaxSelectStmtOffset returns the current stmt offset.

type HintsSet

type HintsSet struct {
	// contains filtered or unexported fields
}

HintsSet contains all hints of a query.

func CollectHint

func CollectHint(in ast.StmtNode) *HintsSet

CollectHint collects hints for a statement.

func ParseHintsSet

func ParseHintsSet(p *parser.Parser, sql, charset, collation, db string) (*HintsSet, ast.StmtNode, []error, error)

ParseHintsSet parses a SQL string, then collects and normalizes the HintsSet.

func (*HintsSet) ContainTableHint

func (hs *HintsSet) ContainTableHint(hint string) bool

ContainTableHint checks whether the table hint set contains a hint.

func (*HintsSet) GetFirstTableHints

func (hs *HintsSet) GetFirstTableHints() []*ast.TableOptimizerHint

GetFirstTableHints gets the first table hints.

func (*HintsSet) Restore

func (hs *HintsSet) Restore() (string, error)

Restore returns the string format of HintsSet.

type NodeType

type NodeType int

NodeType indicates if the node is for SELECT / UPDATE / DELETE.

const (
	// TypeUpdate for Update.
	TypeUpdate NodeType = iota
	// TypeDelete for DELETE.
	TypeDelete
	// TypeSelect for SELECT.
	TypeSelect
	// TypeInvalid for unexpected statements.
	TypeInvalid
)