PolarDB supports three engines: MySQL, PostgreSQL and Oracle.

Which of the following methods can NOT be used for operating Alibaba Cloud Elastic Compute Service (ECS) instances?

You can create an event notification rule in Message Service and push notifications to the specified consumer in the form of messages, to receive events from specified Alibaba Cloud resources. Which of the following options are correct statements about the Message Service (MS) service? (Number of correct answers: 2)

________________ is a fully-managed event-driven computing service that allows you to run code in an elastic and reliable way?

A developer has written a web application using a microservice architecture, in such an architecture, the client (web browser or mobile application) first initiates a request. The request first reaches the load balancer, then goes through an authentication service, a billing service, then requests a resource, and finally a result is returned. How many spans does such a call chain consist of?