Real-Time Synchronization

Precautions

The performance indicators provided in this section are for reference only. The actual environment is affected by factors such as the performance of the source or destination database, network bandwidth, data model, and service model.

Specifications

Based on the performance of data flow types, there are four types of specifications: micro, small, medium, and large. Table 1 lists the performance upper limit of each specification.

**Table 1** Performance upper limit
Specifications	Reference Values of Maximum Performance (Rows/Second)
Micro	300
Small	3,000
Medium	7,500
Large	> 7,500

The performance of each specification is affected by factors such as the networks, source and destination database performance, and latency. The values in the table are for reference only.
DRS measures the performance of different specifications using the full (with flow control disabled) and incremental synchronization tasks as the standard.
The maximum performance (row/second) is measured by the number of transactions synchronized per second. The statement types include BEGIN, COMMIT, DML (INSERT, DELETE, and UPDATE), and DDL.
Currently, DRS supports specification upgrade only in MySQL-to-MySQL synchronization tasks with single-node DRS instances configured. Task specifications cannot be downgraded. For details, see Changing Specifications.
If you want to compare values and the DRS task you create supports value comparison, select a large specification for your DRS instance when creating the DRS task.

Testing Models

Create a full+incremental real-time synchronization task for two RDS for MySQL instances. Table 2 shows the instance configurations.

**Table 2** Instance specifications
Parameter	Source RDS for MySQL instance	Destination RDS for MySQL instance
Flavor	c6.4xlarge.4 (general-enhanced II)	c6.4xlarge.4 (general-enhanced II)
Instance specifications	Ultra-high I/O	Ultra-high I/O
Storage type	16 vCPUs\|64 GB	16 vCPUs\|64 GB
Storage space	300 GB	300 GB
Maximum connections	18,000	18,000
Maximum QPS	3,325	3,325
Maximum IOPS	114,152	114,152

Test model:

The number of test tables is 20.
All test tables have primary keys.
The record size is 1 KB.
Each transaction contains two DML operations and one COMMIT operation. The ratio of INSERT, UPDATE, and DELETE operations is 1:1:1.

Multiple Specifications

DRS real-time synchronization allows you to select specifications for some specified data flow tasks, but the specifications cannot be changed after a task is created.

**Table 3** Data flow types that support multiple specifications
Synchronization Direction	Data Flow	Multiple Specifications
To the cloud	MySQL->MySQL	Yes
To the cloud	MySQL->PostgreSQL	Yes
To the cloud	MySQL -> GaussDB distributed	No
To the cloud	MySQL -> GaussDB primary/standby	No
To the cloud	MySQL->GaussDB(DWS)	Yes
To the cloud	MySQL->GaussDB(for MySQL)	Yes
To the cloud	PostgreSQL->PostgreSQL	Yes
To the cloud	PostgreSQL->GaussDB(DWS)	No
To the cloud	PostgreSQL -> GaussDB primary/standby	No
To the cloud	PostgreSQL -> GaussDB distributed	No
To the cloud	DDM->MySQL	Yes
To the cloud	DDM->GaussDB(DWS)	Yes
To the cloud	DDM->DDM	Yes
To the cloud	Oracle->GaussDB(DWS)	Yes
To the cloud	Oracle->PostgreSQL	Yes
To the cloud	Oracle->MySQL	Yes
To the cloud	Oracle->GaussDB(for MySQL)	Yes
To the cloud	Oracle -> GaussDB primary/standby	No
To the cloud	Oracle -> GaussDB distributed	No
To the cloud	Oracle->DDM	Yes
To the cloud	DB2 for LUW -> GaussDB primary/standby	No
To the cloud	DB2 for LUW -> GaussDB distributed	No
To the cloud	DB2 for LUW->GaussDB(DWS)	No
To the cloud	TiDB->GaussDB(for MySQL)	No
To the cloud	Microsoft SQL Server->GaussDB(DWS)	No
To the cloud	Microsoft SQL Server -> GaussDB primary/standby	No
To the cloud	Microsoft SQL Server -> GaussDB distributed	No
To the cloud	Microsoft SQL Server->Microsoft SQL Server	No
To the cloud	MongoDB->DDS	No
From the cloud	MySQL->MySQL	Yes
From the cloud	MySQL->Kafka	Yes
From the cloud	MySQL->CSS/ES	Yes
From the cloud	MySQL->Oracle	Yes
From the cloud	DDM->MySQL	Yes
From the cloud	DDM->Oracle	Yes
From the cloud	DDM->Kafka	Yes
From the cloud	DDS->MongoDB	Yes
From the cloud	PostgreSQL->Kafka	Yes
From the cloud	GaussDB primary/standby -> MySQL	No
From the cloud	GaussDB primary/standby -> Oracle	No
From the cloud	GaussDB primary/standby -> Kafka	Yes
From the cloud	GaussDB primary/standby -> GaussDB(DWS)	Yes
From the cloud	GaussDB primary/standby -> GaussDB distributed	No
From the cloud	GaussDB primary/standby -> GaussDB primary/standby	No
From the cloud	GaussDB distributed -> MySQL	No
From the cloud	GaussDB distributed -> Oracle	No
From the cloud	GaussDB distributed -> GaussDB(DWS)	Yes
From the cloud	GaussDB distributed -> Kafka	Yes
From the cloud	GaussDB distributed -> GaussDB distributed	No
From the cloud	GaussDB distributed->GaussDB primary/standby	No
From the cloud	GaussDB(for MySQL)->MySQL	Yes
From the cloud	GaussDB(for MySQL)->GaussDB(DWS)	Yes
From the cloud	GaussDB(for MySQL)->Kafka	Yes
From the cloud	GaussDB(for MySQL)->CSS/ES	Yes
From the cloud	GaussDB(for MySQL)->Oracle	Yes
Self-built -> Self-built	MySQL->Kafka	Yes
Self-built -> Self-built	MySQL->CSS/ES	Yes
Self-built -> Self-built	Oracle->Kafka	Yes
Self-built -> Self-built	Oracle -> GaussDB primary/standby	No
Self-built -> Self-built	Oracle -> GaussDB distributed	No
Self-built -> Self-built	PostgreSQL->Kafka	Yes
Self-built -> Self-built	GaussDB primary/standby -> Oracle	No
Self-built -> Self-built	GaussDB primary/standby -> Kafka	Yes
Self-built -> Self-built	GaussDB distributed -> Oracle	No
Self-built -> Self-built	GaussDB distributed -> Kafka	Yes