Method init

db.go:646–689

init creates a new database file and initializes its meta pages.

()

// init creates a new database file and initializes its meta pages.
func (db *DB) init() error {
	// Create two meta pages on a buffer.
	buf := make([]byte, db.pageSize*4)
	for i := 0; i < 2; i++ {
		p := db.pageInBuffer(buf, common.Pgid(i))
		p.SetId(common.Pgid(i))
		p.SetFlags(common.MetaPageFlag)

		// Initialize the meta page.
		m := p.Meta()
		m.SetMagic(common.Magic)
		m.SetVersion(common.Version)
		m.SetPageSize(uint32(db.pageSize))
		m.SetFreelist(2)
		m.SetRootBucket(common.NewInBucket(3, 0))
		m.SetPgid(4)
		m.SetTxid(common.Txid(i))
		m.SetChecksum(m.Sum64())
	}

	// Write an empty freelist at page 3.
	p := db.pageInBuffer(buf, common.Pgid(2))
	p.SetId(2)
	p.SetFlags(common.FreelistPageFlag)
	p.SetCount(0)

	// Write an empty leaf page at page 4.
	p = db.pageInBuffer(buf, common.Pgid(3))
	p.SetId(3)
	p.SetFlags(common.LeafPageFlag)
	p.SetCount(0)

	// Write the buffer to our data file.
	if _, err := db.ops.writeAt(buf, 0); err != nil {
		db.Logger().Errorf("writeAt failed: %w", err)
		return err
	}
	if err := fdatasync(db); err != nil {
		db.Logger().Errorf("[GOOS: %s, GOARCH: %s] fdatasync failed: %w", runtime.GOOS, runtime.GOARCH, err)
		return err
	}

	return nil
}

// Close releases all database resources.
// It will block waiting for any open transactions to finish