Method NextSQL

pkg/ttl/sqlbuilder/sql.go:339–374

NextSQL creates next sql of the scan task

(continueFromResult [][]types.Datum, nextLimit int)

// NextSQL creates next sql of the scan task
func (g *ScanQueryGenerator) NextSQL(continueFromResult [][]types.Datum, nextLimit int) (string, error) {
	if g.exhausted {
		return "", errors.New("generator is exhausted")
	}

	if nextLimit <= 0 {
		return "", errors.Errorf("invalid limit '%d'", nextLimit)
	}

	defer func() {
		g.firstBuild = false
	}()

	if g.stack == nil {
		g.stack = make([][]types.Datum, 0, len(g.tbl.KeyColumns))
	}

	if len(continueFromResult) >= g.limit {
		var continueFromKey []types.Datum
		if cnt := len(continueFromResult); cnt > 0 {
			continueFromKey = continueFromResult[cnt-1]
		}
		if err := g.setStack(continueFromKey); err != nil {
			return "", err
		}
	} else {
		if l := len(g.stack); l > 0 {
			g.stack = g.stack[:l-1]
		}
		if len(g.stack) == 0 {
			g.exhausted = true
		}
	}
	g.limit = nextLimit
	return g.buildSQL()
}

// IsExhausted returns whether the generator is exhausted
func (g *ScanQueryGenerator) IsExhausted() bool {