ClickHouse/docs/en/system_tables/system.zookeeper.md
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# system.zookeeper
Allows reading data from the ZooKeeper cluster defined in the config.
The query must have a 'path' equality condition in the WHERE clause. This is the path in ZooKeeper for the children that you want to get data for.
The query `SELECT * FROM system.zookeeper WHERE path = '/clickhouse'` outputs data for all children on the `/clickhouse` node.
To output data for all root nodes, write path = '/'.
If the path specified in 'path' doesn't exist, an exception will be thrown.
Columns:
```text
name String - Name of the node.
path String - Path to the node.
value String - Value of the node.
dataLength Int32 - Size of the value.
numChildren Int32 - Number of children.
czxid Int64 - ID of the transaction that created the node.
mzxid Int64 - ID of the transaction that last changed the node.
pzxid Int64 - ID of the transaction that last added or removed children.
ctime DateTime - Time of node creation.
mtime DateTime - Time of the last node modification.
version Int32 - Node version - the number of times the node was changed.
cversion Int32 - Number of added or removed children.
aversion Int32 - Number of changes to ACL.
ephemeralOwner Int64 - For ephemeral nodes, the ID of the session that owns this node.
```
Example:
```sql
SELECT *
FROM system.zookeeper
WHERE path = '/clickhouse/tables/01-08/visits/replicas'
FORMAT Vertical
```
```text
Row 1:
──────
name: example01-08-1.yandex.ru
value:
czxid: 932998691229
mzxid: 932998691229
ctime: 2015-03-27 16:49:51
mtime: 2015-03-27 16:49:51
version: 0
cversion: 47
aversion: 0
ephemeralOwner: 0
dataLength: 0
numChildren: 7
pzxid: 987021031383
path: /clickhouse/tables/01-08/visits/replicas
Row 2:
──────
name: example01-08-2.yandex.ru
value:
czxid: 933002738135
mzxid: 933002738135
ctime: 2015-03-27 16:57:01
mtime: 2015-03-27 16:57:01
version: 0
cversion: 37
aversion: 0
ephemeralOwner: 0
dataLength: 0
numChildren: 7
pzxid: 987021252247
path: /clickhouse/tables/01-08/visits/replicas
```