Contains information about tasks from replication queues stored in ZooKeeper for tables in the
database(String) — Name of the database.
table(String) — Name of the table.
replica_name(String) — Replica name in ZooKeeper. Different replicas of the same table have different names.
position(UInt32) — Position of the task in the queue.
node_name(String) — Node name in ZooKeeper.
type(String) — Type of the task in the queue, one of:
GET_PART— Get the part from another replica.
ATTACH_PART— Attach the part, possibly from our own replica (if found in the
detachedfolder). You may think of it as a
GET_PARTwith some optimizations as they're nearly identical.
MERGE_PARTS— Merge the parts.
DROP_RANGE— Delete the parts in the specified partition in the specified number range.
CLEAR_COLUMN— NOTE: Deprecated. Drop specific column from specified partition.
CLEAR_INDEX— NOTE: Deprecated. Drop specific index from specified partition.
REPLACE_RANGE— Drop a certain range of parts and replace them with new ones.
MUTATE_PART— Apply one or several mutations to the part.
ALTER_METADATA— Apply alter modification according to global /metadata and /columns paths.
create_time(Datetime) — Date and time when the task was submitted for execution.
required_quorum(UInt32) — The number of replicas waiting for the task to complete with confirmation of completion. This column is only relevant for the
source_replica(String) — Name of the source replica.
new_part_name(String) — Name of the new part.
is_detach(UInt8) — The flag indicates whether the
DETACH_PARTStask is in the queue.
is_currently_executing(UInt8) — The flag indicates whether a specific task is being performed right now.
num_tries(UInt32) — The number of failed attempts to complete the task.
last_exception(String) — Text message about the last error that occurred (if any).
last_attempt_time(Datetime) — Date and time when the task was last attempted.
num_postponed(UInt32) — The number of postponed tasks.
postpone_reason(String) — The reason why the task was postponed.
last_postpone_time(Datetime) — Date and time when the task was last postponed.
merge_type(String) — Type of the current merge. Empty if it's a mutation.
SELECT * FROM system.replication_queue LIMIT 1 FORMAT Vertical;
create_time: 2020-12-07 14:04:21
last_exception: Code: 226, e.displayText() = DB::Exception: Marks file '/opt/clickhouse/data/merge/visits_v2/tmp_fetch_20201130_121373_121384_2/CounterID.mrk' does not exist (version 18.104.22.168 (official build))
last_attempt_time: 2020-12-08 17:35:54
last_postpone_time: 1970-01-01 03:00:00