Method Commit

tx.go:170–283

Commit writes all changes to disk, updates the meta page and closes the transaction. Returns an error if a disk write error occurs, or if Commit is called on a read-only transaction.

()

// Returns an error if a disk write error occurs, or if Commit is
// called on a read-only transaction.
func (tx *Tx) Commit() (err error) {
	txId := tx.ID()
	lg := tx.db.Logger()
	if lg != discardLogger {
		lg.Debugf("Committing transaction %d", txId)
		defer func() {
			if err != nil {
				lg.Errorf("Committing transaction failed: %v", err)
			} else {
				lg.Debugf("Committing transaction %d successfully", txId)
			}
		}()
	}

	common.Assert(!tx.managed, "managed tx commit not allowed")
	if tx.db == nil {
		return berrors.ErrTxClosed
	} else if !tx.writable {
		return berrors.ErrTxNotWritable
	}

	// TODO(benbjohnson): Use vectorized I/O to write out dirty pages.

	// Rebalance nodes which have had deletions.
	var startTime = time.Now()
	tx.root.rebalance()
	if tx.stats.GetRebalance() > 0 {
		tx.stats.IncRebalanceTime(time.Since(startTime))
	}

	opgid := tx.meta.Pgid()

	// spill data onto dirty pages.
	startTime = time.Now()
	if err = tx.root.spill(); err != nil {
		lg.Errorf("spilling data onto dirty pages failed: %v", err)
		tx.rollback()
		return err
	}
	tx.stats.IncSpillTime(time.Since(startTime))

	// Free the old root bucket.
	tx.meta.RootBucket().SetRootPage(tx.root.RootPage())

	// Free the old freelist because commit writes out a fresh freelist.
	if tx.meta.Freelist() != common.PgidNoFreelist {
		tx.db.freelist.Free(tx.meta.Txid(), tx.db.page(tx.meta.Freelist()))
	}

	if !tx.db.NoFreelistSync {
		err = tx.commitFreelist()
		if err != nil {
			lg.Errorf("committing freelist failed: %v", err)
			return err
		}
	} else {
		tx.meta.SetFreelist(common.PgidNoFreelist)
	}