system/Database/BaseConnection.php
public function transComplete(): bool
	{
		if (! $this->transEnabled)
		{
			return false;
		}

		// The query() function will set this flag to FALSE in the event that a query failed
		if ($this->transStatus === false || $this->transFailure === true)
		{
			$this->transRollback();

			// If we are NOT running in strict mode, we will reset
			// the _trans_status flag so that subsequent groups of
			// transactions will be permitted.
			if ($this->transStrict === false)
			{
				$this->transStatus = true;
			}

			//            log_message('debug', 'DB Transaction Failure');
			return false;
		}

		return $this->transCommit();
	}
public function transComplete(): bool
	{
		if (! $this->transEnabled)
		{
			return false;
		}

		// The query() function will set this flag to FALSE in the event that a query failed
		if ($this->transStatus === false || $this->transFailure === true)
		{
			$this->transRollback();

			// If we are NOT running in strict mode, we will reset
			// the _trans_status flag so that subsequent groups of
			// transactions will be permitted.
			if ($this->transStrict === false)
			{
				$this->transStatus = true;
			}

			//            log_message('debug', 'DB Transaction Failure');
			return false;
		}

		return $this->transCommit();
	}
Complete Transaction

@return boolean