system.zookeeper_watches

System table showing currently active ZooKeeper watches registered by this ClickHouse server.

Description

Shows currently active watches registered by this ClickHouse server on ZooKeeper nodes (including auxiliary ZooKeepers). Each row represents one watch.

Columns

• zookeeper_name (String) — Name of the ZooKeeper connection (default for the main connection, or the auxiliary name).
• create_time (DateTime) — Time when the watch was created.
• create_time_microseconds (DateTime64) — Time when the watch was created with microsecond precision.
• path (String) — ZooKeeper path being watched.
• session_id (Int64) — Session ID of the connection that registered the watch.
• request_xid (Int64) — XID of the request that created the watch.
• op_num (Enum) — The type of the request that created the watch.
• watch_type (Enum8) — Watch type. Possible values:
  • Children — watching for changes in the list of child nodes (set by List operations).
  • Exists — watching for node creation or deletion.
  • Data — watching for changes in node data (set by Get operations).

Example:

SELECT * FROM system.zookeeper_watches FORMAT Vertical;

Row 1:
──────
zookeeper_name:           default
create_time:              2026-03-16 12:00:00
create_time_microseconds: 2026-03-16 12:00:00.123456
path:                     /clickhouse/task_queue/ddl
session_id:               106662742089334927
request_xid:              10858
op_num:                   List
watch_type:               Children

See Also

• ZooKeeper
• ZooKeeper guide