A developer recently discovered that their company's application is beginning to suffer performance degradation as a result of increased user demand for the application. After some analysis, the major bottleneck is discovered to be the RDS database instance which hosts the company's databases, "A" and "B". The developer plans to use the DTS data migration solution to move one of the databases to a new RDS instance.
Which of the following statements is correct? (Number of correct answers: 3)

• A.Create a reverse data migration task and start it to migrate subsequent incremental data from target Instance database B to source instance database B.
• B.After disconnecting the connection between the source instance database B and the application, you need to log in to the source database B to check the session messages to ensure that no new sessions performed write operations.
• C.The database account used for data migration must have read and write permissions. To ensure database security, please delete the database account used for data migration or reclaim related write permissions after data migration is completed.
• D.The code for the application will have to be rewritten once this migration is complete.

Comment: *

Name: *

Email: *

Verification: *

Which of the following statements about PolarDB's endpoint(s) is NOT correct?

• A.The primary endpoint supports read/write splitting.
• B.The endpoint of the PolarDB MySQL database includes the cluster endpoint and the primary endpoint.
• C.Cluster endpoints support read/write splitting.
• D.Through a cluster endpoint, applications can connect to data nodes.

Comment: *

Name: *

Email: *

Verification: *

Serverless Workflow allows you to orchestrate distributed tasks in sequence, branch, and parallel modes, and ensure that tasks are reliably coordinated according to your workflow logic. Which of the following service integration modes is not supported by Serverless Workflow?

• A.Asynchronous mode
• B.Request response mode
• C.Synchronization mode
• D.Waiting for callback mode

Comment: *

Name: *

Email: *

Verification: *

Which of the following is NOT a feature of Alibaba Cloud's Cassandra database service?

• A.Enterprise-level capabilities such as disaster tolerance, backup and recovery, security, and monitoring across data centers
• B.Supports both narrow and wide tables, providing flexible schema functions
• C.Cluster storage, strong expansion of read and write capabilities
• D.Centerless distributed architecture

Comment: *

Name: *

Email: *

Verification: *

Which of the following statements describe the trace/D and spanID in a service tracking system (such as Zipkin) correctly? (Number of correct answers: 3)

• A.When the user's request enters the system, a globally unique traceld will be generated on the first layer of the calling network.
• B.Traceld is used to distinguish the sequence of calls between different services of the system, spanld is used to concatenate all the paths that a certain request traverses in the system.
• C.The tracelD will be called with each layer and passed back continuously, so through traceld, the path of a user request in the system can be connected in series.
• D.Spanld can locate the position of a request in the system call, and who its upstream and downstream dependencies are respectively.

Comment: *

Name: *

Email: *

Verification: *