v.23.10Improvement
ClickHouse Enhances ReplicatedMergeTree Startup by Restoring Closest Ancestor Parts
During ReplicatedMergeTree tables startup clickhouse server checks set of parts for unexpected parts (exists locally, but not in zookeeper). All unexpected parts move to detached directory and instead of them server tries to restore some ancestor (covered) parts. Now server tries to restore closest ancestors instead of random covered parts. #55645 (alesapin).
Why it matters
WhenReplicatedMergeTree tables start, the server checks for unexpected parts (parts present locally but missing in ZooKeeper). Previously, the server detached these unexpected parts and attempted to restore some random covered ancestor parts, which could lead to inefficiencies or slower recovery. This feature enhances data consistency and startup reliability by ensuring that the server restores the closest ancestor parts, optimizing the recovery process.How to use it
This improvement is applied automatically during the startup ofReplicatedMergeTree tables. Users do not need to enable or configure anything manually to benefit from this change.