我们看看insert语句的执行过程，

  如果cs.isTransactionStatement()是true，则表示启动事务执行，

 public Result executeCompiledStatement(Statement cs, Object[] pvals) {

        Result r;

        if (abortTransaction) {
            rollback(false);

            return Result.newErrorResult(Error.error(ErrorCode.X_40001));
        }

        if (sessionContext.depth > 0) {
            if (sessionContext.noSQL.booleanValue()
                    || cs.isAutoCommitStatement()) {
                return Result.newErrorResult(Error.error(ErrorCode.X_46000));
            }
        }

        if (cs.isAutoCommitStatement()) {
            if (isReadOnly()) {
                return Result.newErrorResult(Error.error(ErrorCode.X_25006));
            }

            try {

                /** special autocommit for backward compatibility */
                commit(false);
            } catch (HsqlException e) {
                database.logger.logInfoEvent("Exception at commit");
            }
        }

        sessionContext.currentStatement = cs;

        boolean isTX = cs.isTransactionStatement();

        if (!isTX) {
            if (database.logger.getSqlEventLogLevel()
                    >= SimpleLog.LOG_NORMAL) {
                sessionContext.setDynamicArguments(pvals);
                database.logger.logStatementEvent(this, cs, pvals,
                                                  SimpleLog.LOG_NORMAL);
            }

            r                               = cs.execute(this);
            sessionContext.currentStatement = null;

            return r;
        }

        while (true) {
            actionIndex = rowActionList.size();

            database.txManager.beginAction(this, cs);

            cs = sessionContext.currentStatement;

            if (cs == null) {
                return Result.newErrorResult(Error.error(ErrorCode.X_07502));
            }

            if (abortTransaction) {
                rollback(false);

                sessionContext.currentStatement = null;

                return Result.newErrorResult(Error.error(ErrorCode.X_40001));
            }

            try {
                latch.await();
            } catch (InterruptedException e) {
                abortTransaction = true;
            }

            if (abortTransaction) {
                rollback(false);

                sessionContext.currentStatement = null;

                return Result.newErrorResult(Error.error(ErrorCode.X_40001));
            }

            database.txManager.beginActionResume(this);

            //        tempActionHistory.add("sql execute " + cs.sql + " " + actionTimestamp + " " + rowActionList.size());
            sessionContext.setDynamicArguments(pvals);

            if (database.logger.getSqlEventLogLevel()
                    >= SimpleLog.LOG_NORMAL) {
                database.logger.logStatementEvent(this, cs, pvals,
                                                  SimpleLog.L