system.distributed_ddl_queue

System table containing information about distributed ddl queries (queries using the ON CLUSTER clause) that were executed on a cluster.

Description

Contains information about distributed ddl queries (ON CLUSTER clause) that were executed on a cluster.

Columns

• entry (String) — Query id.
• entry_version (Nullable(UInt8)) — Version of the entry.
• initiator_host (Nullable(String)) — Host that initiated the DDL operation.
• initiator_port (Nullable(UInt16)) — Port used by the initiator.
• cluster (String) — Cluster name, empty if not determined.
• query (String) — Query executed.
• settings (Map(String, String)) — Settings used in the DDL operation.
• query_create_time (DateTime) — Query created time.
• host (Nullable(String)) — Hostname.
• port (Nullable(UInt16)) — Host Port.
• status (Nullable(Enum8(‘Inactive’ = 0, ‘Active’ = 1, ‘Finished’ = 2, ‘Removing’ = 3, ‘Unknown’ = 4))) — Status of the query.
• exception_code (Nullable(UInt16)) — Exception code.
• exception_text (Nullable(String)) — Exception message.
• query_finish_time (Nullable(DateTime)) — Query finish time.
• query_duration_ms (Nullable(UInt64)) — Duration of query execution (in milliseconds).

Example

SELECT *
FROM system.distributed_ddl_queue
WHERE cluster = 'test_cluster'
LIMIT 2
FORMAT Vertical

Query id: f544e72a-6641-43f1-836b-24baa1c9632a

Row 1:
──────
entry:             query-0000000000
entry_version:     5
initiator_host:    clickhouse01
initiator_port:    9000
cluster:           test_cluster
query:             CREATE DATABASE test_db UUID '4a82697e-c85e-4e5b-a01e-a36f2a758456' ON CLUSTER test_cluster
settings:          {'max_threads':'16','use_uncompressed_cache':'0'}
query_create_time: 2023-09-01 16:15:14
host:              clickhouse-01
port:              9000
status:            Finished
exception_code:    0
exception_text:
query_finish_time: 2023-09-01 16:15:14
query_duration_ms: 154

Row 2:
──────
entry:             query-0000000001
entry_version:     5
initiator_host:    clickhouse01
initiator_port:    9000
cluster:           test_cluster
query:             CREATE DATABASE test_db UUID '4a82697e-c85e-4e5b-a01e-a36f2a758456' ON CLUSTER test_cluster
settings:          {'max_threads':'16','use_uncompressed_cache':'0'}
query_create_time: 2023-09-01 16:15:14
host:              clickhouse-01
port:              9000
status:            Finished
exception_code:    630
exception_text:    Code: 630. DB::Exception: Cannot drop or rename test_db, because some tables depend on it:
query_finish_time: 2023-09-01 16:15:14
query_duration_ms: 154

2 rows in set. Elapsed: 0.025 sec.