Terms

The terms in this glossary are sorted alphabetically.

B

BizType

BizType is a unique identifier for a business scenario. The client data synchronization SDK uses the BizType to distribute pushed data to the corresponding business module.

C

Persistence

Persistence is the mechanism that converts program data between persistent and transient states. In the data synchronization service, this mechanism enables two data behaviors: persistent and non-persistent.

• Persistent data: When a user or device is offline, the data is persisted to the database. After the user or device comes online, the data synchronization SDK triggers synchronization.

• Non-persistent data: When a user or device is online, the data is pushed immediately. If they are offline, the data is discarded. The user cannot receive this data after coming online again.

D

Single-device push

Single-device push sends a message only once to the user's most recently online device when data is pushed based on the user dimension. The system does not resend the data if the user uninstalls and reinstalls the client or comes online on a different device.

Multi-device synchronization

With multi-device synchronization, data pushed based on the user dimension is synchronized across all of a user's devices. A user who switches devices will still receive data that was previously delivered to another device. If the user uninstalls and reinstalls the client, the data is pushed again after the user comes online.

H

Background

Background refers to the state where the client app is running but is not the active application. This occurs when the user is on the phone's home screen, using another app, or the phone screen is off.

M

Idempotence

Idempotence ensures that duplicate data is discarded based on the thirdMsgId field in SyncOrder. The combination of bizType, linkToken, and thirdMsgId must be unique. This allows an operation to succeed only once. If a duplicate operation is attempted, the API call returns a success message with the result code DUPLICATED_BIZ_ID.

MSS data

This refers to data that is pushed by the data synchronization server.

MSS push

MSS push is the process of actively sending data from the server-side to a client. If the client is online, the push is triggered immediately. If the client is offline, the data is pushed after the client comes online.

Q

Foreground

The client app is open.

S

SYNC

SYNC is the data synchronization service that synchronizes data from the server-side to the client app.

T

Push type

There are two push types: targeted push and global push.

• Targeted push: Pushes data to a specific userId or utdId.

• Global push: Pushes data to all online users or devices. Global push uses multi-device synchronization.

Y

Business dimension

Business dimension refers to the scope of data synchronization. It can be either the user dimension or the device dimension. The user dimension pushes data based on a userId. The device dimension pushes data based on a utdId.

Threshold

A threshold is the maximum amount of backlogged data allowed on the server. A data backlog can occur if a user or device is offline for an extended period while the MSS server continues to generate new data. When the backlog exceeds the threshold, older data is discarded, and only the most recent data is retained.

Z

Online

A client app is considered online when it has a network connection and can maintain a stable, long-lived TCP connection.

Most Android phones allow an app to stay online while in the background. On iOS devices, an app can stay online in the background for three minutes due to operating system limitations.