AnalyticDB:XUANWU_V2 engine

Prerequisites

• An AnalyticDB for MySQL Enterprise Edition, Basic Edition, or Data Lakehouse Edition cluster is created.

• The minor version of the cluster is 3.2.2.0 or later.

  Note

  To view and update the minor version of an AnalyticDB for MySQL cluster, log on to the AnalyticDB for MySQL console and go to the Configuration Information section of the Cluster Information page.

Overview

AnalyticDB for MySQL uses the XUANWU analytical storage engine to perform high-throughput writes and high-performance queries in real time. The next-generation storage engine, XUANWU_V2, provides the following features:

• Stores all data in Object Storage Service (OSS) and uses cloud disks as a cache. This reduces storage costs, ensures query performance, and provides faster scale-out capabilities and higher scaling efficiency.

• Provides the next-generation column-oriented storage. The new storage format provides finer-grained control over memory usage and disk I/O, supports highly concurrent I/O operations, and uses fewer memory resources. This improves query performance and reduces impact of garbage collection (GC) on your business.

• Uses the independent compaction service to perform the compaction operations that consume a large amount of resources. This improves query and write stability and provides higher compaction throughput and more flexible resource scheduling capabilities.

Limits

• The XUANWU_V2 engine does not fully support all the features available in the XUANWU engine. The following table describes the comparison results between the two engines.

  Comparison item	XUANWU	XUANWU_V2
  Regular index	By default, full-column indexes are created by using INDEX_ALL='Y'.	By default, indexes are created only for the primary key by using INDEX_ALL='N'. Note Methods to create and modify full-column indexes: Before you create a table, execute the SET ADB_CONFIG XUANWUV2_DEFAULT_INDEX_ALL=true statement at the cluster level to create full-column indexes for the existing and new tables. When you create a table, specify INDEX_ALL='Y' in the CREATE TABLE statement to create full-column indexes for the existing tables. After you create a table, execute the ALTER TABLE statement to modify full-column indexes for the existing tables.
  Vector index	Supported	Not supported
  Binary log	Supported	Not supported
  Spark elastic import	Supported	Not supported

• The XUANWU and XUANWU_V2 engines cannot be switched between each other. If you want to change the table engine of a table, you must create a new table and migrate data from the source table to the new table.

  For example, the table engine of the test table is XUANWU_V2 and cannot be changed to XUANWU. You can create a table whose table engine is XUANWU and migrate data from the test table to the new table.

Billing rules

By default, the data of XUANWU_V2 tables is considered hot data and is billed based on hot data storage. If you specify tiered storage of hot and cold data for XUANWU_V2 tables, the data of XUANWU_V2 tables is billed based on hot data storage and cold data storage. For more information, see Pricing for Enterprise Edition and Basic Edition and Pricing for Data Lakehouse Edition.

Specify a table engine

For AnalyticDB for MySQL clusters of V3.2.2.0 or later, the default table engine is XUANWU_V2. You can change the table engine at the cluster or table level.

SET ADB_CONFIG RC_DDL_ENGINE_REWRITE_XUANWUV2=false|true;

SHOW ADB_CONFIG KEY=RC_DDL_ENGINE_REWRITE_XUANWUV2;

/* RC_DDL_ENGINE_REWRITE_XUANWUV2=false|true */

Enable the disk cache feature

The cold data of XUANWU_V2 tables is stored in OSS. After you enable the disk cache feature, you can use the specified cache to improve the random cold data read performance of XUANWU_V2 tables. You are charged based on the specified cache size.

We recommend that you do not disable the disk cache feature to prevent serious performance degradation.

1. Log on to the AnalyticDB for MySQL console. In the upper-left corner of the console, select a region. In the left-side navigation pane, click Clusters. Find the cluster that you want to manage and click the cluster ID.

2. In the Configuration Information section of the Cluster Information page, click Configure next to the Cluster Query Acceleration Configuration parameter.

3. In the Cluster Query Acceleration Configuration dialog box, click the Disk Cache tab. Turn on and specify a cache size.

Enable the compaction service

The compaction service uses an independent resource pool to perform local compaction operations in an independent process. This reduces resource usage and improves service stability. By default, the compaction service is disabled. After you enable the compaction service, you are charged for the compaction service based on the pay-as-you-go billing method. You can disable the compaction service based on your business requirements. For more information, see Pricing for Enterprise Edition and Basic Edition and Pricing for Data Lakehouse Edition.

We recommend that you enable the compaction service in scenarios that meet the following conditions:

• The CPU utilization and the memory usage are high.

• The service performance is significantly affected by scheduled compaction operations.