tx: update max_transactions description #28233
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Pull Request Overview
This PR updates the documentation strings for two transaction-related configuration parameters to provide clearer guidance and warnings about memory management. The changes align the in-code descriptions with external documentation.
Key Changes:
- Enhanced
transactional_id_expiration_msdescription to explain automatic producer ID cleanup and warn about high-churn workloads - Expanded
max_concurrent_producer_idsdescription to clarify per-shard behavior, LRU eviction policy, and importantly warn about the default unlimited value potentially causing OOM crashes
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| "Maximum number of active producer sessions per shard. Each shard " | ||
| "tracks producer IDs using an LRU (Least Recently Used) eviction " | ||
| "policy. When the configured limit is exceeded, the least recently " | ||
| "used producer IDs are evicted from the cache. IMPORTANT: The default " | ||
| "value is unlimited, which can lead to unbounded memory growth and " | ||
| "out-of-memory (OOM) crashes in production environments with heavy " | ||
| "producer usage, especially when using transactions or idempotent " | ||
| "producers. It is strongly recommended to set a reasonable limit in " | ||
| "production deployments.", |
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The description states 'When the configured limit is exceeded, the least recently used producer IDs are evicted from the cache,' but this behavior only applies when a limit is actually set. With the default unlimited value, no eviction occurs. Consider clarifying that eviction only happens when a finite limit is configured, e.g., 'When a finite limit is configured and exceeded, the least recently used producer IDs are evicted from the cache.'
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CI test resultstest results on build#75119
|
bharathv
approved these changes
Oct 29, 2025
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Update description of
max_concurrent_producer_idsandtransactional_id_expiration_msto match docs at
redpanda-data/docs#1425
Backports Required
Release Notes
Improvements
max_concurrent_producer_idsandtransactional_id_expiration_mswith details to prevent OOM scenarios.