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Terms

Last Updated: Jun 21, 2018

This topic explains common terms involved in MQ Open API for reference.

Gateway parameters

RegionId

It refers to the region where Alibaba Cloud products are located, including cn-beijing, cn-hangzhou, etc. You need to set the corresponding region before calling Open API. For example, you need to set the region of cn-beijing before operating the MQ resource in north China 2. Refer to the table in Homepage for related information.

OnsRegionId

It refers to the information of the region defined by MQ products. It is used for parameters requested by API, and specifying API to operate MQ resources in corresponding regions. The information of the region needs to be obtained according to the OnsRegionList interface.

EndPoint

Open API calls the corresponding back-end service according to the set access point. It is set as the corresponding RegionId.

Domain

Open API calls the corresponding backend service according to the set access domain name. For example, the domain is “ ons.cn-hangzhou.aliyuncs.com”, which indicates that the MQ backend service of east China 1 is linked. Refer to Access Guide for specific domain name information. (44419)

Account security parameters

AccessKey

AK of the account used for accessing Alibaba Cloud products. It is obtained from the Alibaba Cloud official website. It is transferred to the MQ backend for identity authentication during calls. Only resources in corresponding accounts can be operated when calling MQ Open API.

SecretKey

It refers to an AK secret key of the account used for accessing Alibaba Cloud products. It is obtained from the Alibaba Cloud official website and transferred during calls for calculating the signature of the access request. MQ backend compares the corresponding account with the signature for authentication.

MQ resource management and control parameters

Topic

Messages in MQ products are stored by Topic. Therefore, Topic is one of the most important resources in MQ. Topic is globally unique in MQ.

ProducerId (PID)

It is the unique ID for determining the publish relation in MQ products, and is used to identify a sent cluster. ProducerId is globally unique in MQ. PID is how it is referenced in subsequent documents.

ConsumerId (CID)

It is the unique ID for determining the subscribe relation in MQ products, and is used to identify a consumer. Logic of consumed messages of clients using the same ConsumerId must be completely consistent. ConsumerId is globally unique in MQ. CID is how it is referenced in subsequent documents.

Message Accumulation

It describes message data in MQ products which has not been processed by consumers. When message production is faster than message consumption, the difference between the produced message and the consumed message is the number of accumulations. Under normal conditions, the number of accumulations should be within a controllable range. If the number of accumulations is too large and seems to increase gradually, you need to focus on the reason why consumers consume messages slowly.

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