Every event stream has a Settings tab where you control how failures are handled, how much parallel capacity the stream has, how long messages are kept, and how to clear out old data. This page walks through each of those controls, what they do, and what to keep in mind before you change them.
Overview
Open an event stream and go to its Settings tab to find four groups of controls: the dead letter queue toggle, the partition count, data retention, and a reset action. Some changes save immediately, and others require you to submit them explicitly — the sections below call out which is which.
Dead Letter Queue
The Enable Dead Letter Queue toggle adds message acknowledgement to the stream and gives failed events somewhere to go instead of disappearing. Turn it on and a companion stream is created and linked automatically, named after your stream with "(DLQ)" appended. A shortcut button appears so you can jump straight to it.
Once acknowledgement is on, consumers confirm each message they process, and anything that fails processing lands in the DLQ stream rather than being lost. Keep in mind that a DLQ stream can't have its own DLQ, so you won't see this toggle when you open a DLQ stream's settings.
Unlike the other settings on this page, switching the toggle on takes effect right away, because it has to create the linked stream at that moment.
Partitions
Partition Count sets how many parallel lanes the stream processes messages on — more partitions mean more consumers can work in parallel. Every stream starts at 1 partition, and you can raise the count up to a maximum of 30.
Raise this number with care: once you increase the partition count, you cannot decrease it again. Set it based on how much parallel consumption you actually expect, and grow it gradually rather than jumping straight to the maximum.
Retention Period
Under Data Management, the Retention Period setting defines how long the stream holds on to messages before removing them automatically. You can express it in minutes, hours, or days; if you never set a value, the stream defaults to one day.
Retention removal happens regardless of whether a message was ever consumed — once a message passes the retention window, it's gone. This also affects what you can see: the Logs tab only shows messages that are still within the retention period, so older activity won't appear there even if it was never read.
Resetting Stream Data
Reset Stream data erases every message currently sitting in the stream, regardless of how much of the retention period is left. This is useful when you want to clear out test data or start fresh without waiting for retention to catch up.
To reset a stream, click Reset and confirm the prompt asking whether you're sure you want to reset the topic. You'll see a confirmation once it's done. Resetting only removes the messages — it does not touch the stream's schema or any of its other settings — and the action cannot be undone, so double-check you're resetting the right stream before confirming.
Notes
Most changes on the Settings tab — partition count and retention period included — only take effect after you click Submit in the footer; Discard Changes reverts anything you haven't submitted yet.
Both Submit and Discard Changes stay disabled until you actually change something.
The Dead Letter Queue toggle is the one exception: turning it on saves immediately since it creates the linked DLQ stream at that moment.
Because partition count can only go up, treat it as a one-way decision and size it for expected growth rather than current load alone.
A stream reset is permanent — there's no way to recover the erased messages afterward.