v.21.7Improvement
Increase background schedule pool size to 128 to prevent replication queue hang
Increase size of background schedule pool to 128 (background_schedule_pool_size setting). It allows avoiding replication queue hung on slow zookeeper connection. #25072 (alesapin).Why it matters
This change addresses issues where the replication queue can hang due to slow ZooKeeper connections. By increasing the background schedule pool size, the system can better handle background tasks concurrently, reducing delays and improving overall replication reliability.How to use it
Users can adjust thebackground_schedule_pool_size setting in the server configuration to 128 or a suitable higher value to benefit from this improvement. This setting controls the number of threads available for scheduling background tasks.