Zero Data Loss

Zero data loss protects a project against data loss in the event of a client failure, server failure, or both. Achieving zero data loss requires a judicious use of log stores when you set up the project, as well as configuration of project options and clients that use guaranteed delivery (GD).

With zero data loss,

Event Stream Processor recovers windows protected by one or more log stores to a consistent state as of the most recent checkpoint. (Any uncheckpointed data is lost and must be sent again by the publisher.)
Clients can be confident they will not miss any events.
Clients can minimize the number of duplicate events they receive by controlling how frequently they issue GD commits.
Publishers can ensure that the data they publish is fully processed by the server and thereby reduce transmission of duplicates when the server restarts.
You can optionally configure the server to control how frequently it issues automatic checkpoints and thus control how much uncheckpointed data is liable to be lost on a server failure.
At the expense of performance, you can minimize (but not fully eliminate) the production of duplicate rows on server or subscriber restart by tweaking how frequently the server checkpoints data and how frequently GD subscribers issue GD commits.

Consistent Recovery
Consistent recovery lets you set up a project that can recover its data if it is interrupted by a server or connection failure.
Auto Checkpoint
Zero data loss relies on data being checkpointed (registered and saved in the project’s log stores). Auto checkpoint lets you configure the checkpoint interval—the number of input transactions that triggers a checkpoint.
Guaranteed Delivery
Guaranteed delivery (GD) uses log stores to ensure that a GD subscriber registered with a GD window receives all the data processed by that window even if the client is not connected when the data is produced.
Achieving Zero Data Loss
A lost connection or a server crash can cause data produced by a project to be lost before it is delivered to a listening client. If you cannot afford to lose data, complete these tasks to configure zero data loss.