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READER_DATA_LIFECYCLE

Controls how long a Subscriber retains samples that have been disposed of or are no longer associated with any Publisher.

What it controls

Delays before the Reader automatically purges disposed samples or samples with no active Writer.

Key settings

Field Default Mutability
autopurge_disposed_samples_delay infinity Can be changed at runtime
autopurge_nowriter_samples_delay infinity Can be changed at runtime

Compatibility role

Lifecycle and disassociation — governs how long disposed or orphaned instances remain in the Reader cache. Interacts with liveliness, durability, and writer autodispose settings.

When this conflicts

Reader Data Lifecycle takes part in the following QoS Guard rules. Each links to a full explanation with an example and a fix.

No-writer purge that never fires because liveliness never expires with LivelinessBreaks a guarantee Disposed-sample purge that discards data durability should keep with DurabilityBreaks a guarantee Immediate no-writer purge with auto-dispose turned off with Writer Data LifecycleBreaks a guarantee Disposed-sample purge that can never fire with Writer Data LifecycleWastes resources Reader cache that is never reclaimed after writers leave with Writer Data LifecycleWastes resources

Example

The RDLIFE QoS policy enables tiered instance management for improved efficiency. For example, in a temporary storage area where hundreds of pallets move quickly and historical positions become obsolete immediately, setting autopurge disposed samples delay to 0 seconds ensures that the cache is cleared as soon as a robot calls dispose(). This keeps the cache lightweight and prevents unnecessary memory growth. In contrast, for static, critical objects awaiting inspection after relocation, setting autopurge no writer samples delay to 300 seconds allows newly joined robots to continue inspection even after brief communication interruptions. By adjusting the reader-side delay values based on context, essential data can be preserved while irrelevant information is promptly discarded, ensuring efficient use of system resources.