# system.zookeeper {#system-zookeeper}

The table does not exist if ZooKeeper is not configured. Allows reading data from the ZooKeeper cluster defined in the config.
The query must have a ‘path’ equality condition in the WHERE clause, or ‘path’ condition in the set 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:

-   `name` (String) — The name of the node.
-   `path` (String) — The path to the node.
-   `value` (String) — Node value.
-   `dataLength` (Int32) — Size of the value.
-   `numChildren` (Int32) — Number of descendants.
-   `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 deleted or added descendants.
-   `ctime` (DateTime) — Time of node creation.
-   `mtime` (DateTime) — Time of the last modification of the node.
-   `version` (Int32) — Node version: the number of times the node was changed.
-   `cversion` (Int32) — Number of added or removed descendants.
-   `aversion` (Int32) — Number of changes to the 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
```
[Original article](https://clickhouse.tech/docs/en/operations/system_tables/zookeeper) <!--hide-->