Method Commit

txn.go:655–676

Commit commits the transaction, following these steps: 1. If there are no writes, return immediately. 2. Check if read rows were updated since txn started. If so, return ErrConflict. 3. If no conflict, generate a commit timestamp and update written rows' commit ts. 4. Batch up all writes, write

()

// If error is nil, the transaction is successfully committed. In case of a non-nil error, the LSM
// tree won't be updated, so there's no need for any rollback.
func (txn *Txn) Commit() error {
	// txn.conflictKeys can be zero if conflict detection is turned off. So we
	// should check txn.pendingWrites.
	if len(txn.pendingWrites) == 0 {
		return nil // Nothing to do.
	}
	// Precheck before discarding txn.
	if err := txn.commitPrecheck(); err != nil {
		return err
	}
	defer txn.Discard()

	txnCb, err := txn.commitAndSend()
	if err != nil {
		return err
	}
	// If batchSet failed, LSM would not have been updated. So, no need to rollback anything.

	// TODO: What if some of the txns successfully make it to value log, but others fail.
	// Nothing gets updated to LSM, until a restart happens.
	return txnCb()
}

type txnCb struct {
	commit func() error