system.replication_queue

    Columns:

    • database (String) — Name of the database.

    • table () — Name of the table.

    • replica_name (String) — Replica name in ZooKeeper. Different replicas of the same table have different names.

    • position () — Position of the task in the queue.

    • node_name (String) — Node name in ZooKeeper.

    • type () — 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 detached folder). You may think of it as a GET_PART with 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.

    • source_replica (String) — Name of the source replica.

    • new_part_name () — Name of the new part.

    • parts_to_merge (Array ()) — Names of parts to merge or update.

    • is_detach (UInt8) — The flag indicates whether the DETACH_PARTS task is in the queue.

    • is_currently_executing () — 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_attempt_time () — Date and time when the task was last attempted.

    • num_postponed (UInt32) — The number of postponed tasks.

    • postpone_reason () — The reason why the task was postponed.

    • last_postpone_time (Datetime) — Date and time when the task was last postponed.

    • merge_type () — Type of the current merge. Empty if it’s a mutation.

    Example

    1. Row 1:
    2. ──────
    4. table:                  visits_v2
    5. position:               15
    6. node_name:              queue-0009325559
    7. type:                   MERGE_PARTS
    8. create_time:            2020-12-07 14:04:21
    9. required_quorum:        0
    10. source_replica:         mtgiga001-1t.metrika.yandex.net
    11. new_part_name:          20201130_121373_121384_2
    12. parts_to_merge:         ['20201130_121373_121378_1','20201130_121379_121379_0','20201130_121380_121380_0','20201130_121381_121381_0','20201130_121382_121382_0','20201130_121383_121383_0','20201130_121384_121384_0']
    13. is_detach:              0
    14. is_currently_executing: 0
    15. num_tries:              36
    16. 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 20.8.7.15 (official build))
    17. last_attempt_time:      2020-12-08 17:35:54
    18. num_postponed:          0
    19. postpone_reason:

    See Also