Feature Description

MySQL Database Write Operations

The Database Management System (DBMS, or database for short) has been widely used in Internet and finance industries.

A database transaction is a series of operations performed by a single logical unit of work. It can be executed completely or not executed completely. Transaction processing ensures that data-oriented resources are not permanently updated unless all operations within the transactional unit are successfully complete.

To ensure consistency and atomicity of the preceding transactions and prevent incomplete transactions submitted to the persistent storage, for example, some data is written to the database and some data is not written to the database due to unexpected power-off, database or OS suspension, many mainstream databases use the doublewrite mechanism, as shown in Figure 1.

As the database uses the doublewrite mechanism to ensure transaction atomicity, each piece of data is written two times.

Implementation of the NVMe SSD Atomic Write Feature

The doublewrite mechanism is used to prevent data inconsistency caused by partial data update and ensure database atomicity. As a result, each piece of data must be written twice.

To address this issue, Huawei ES3000 V5 NVMe SSDs provide the atomic write feature to ensure the atomicity of I/O operations written to the ES3000 V5 NVMe SSDs. With this feature, an I/O is either written completely or fails to be written. It prevents the situation where some data in an I/O is written while some data is not. Figure 2 shows the implementation mechanism.

With the Huawei ES3000 V5 NVMe SSDs, data can be completely written to drives without using the doublewrite mechanism. As one data write operation is eliminated, the performance is improved.

This section describes how to deploy the atomic write feature of Huawei next-generation ES3000 V5 NVMe PCIe SSDs in the MySQL database.

Release Notes

This feature is released with Kunpeng Computing DC Solution 20.0.3.