> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-1d264819.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> System table which exists only if ClickHouse Keeper or ZooKeeper are configured. It exposes data from the Keeper cluster defined in the config.

# system.zookeeper

<h2 id="description">
  Description
</h2>

The table does not exist unless ClickHouse Keeper or ZooKeeper is configured. The `system.zookeeper` table exposes data from the Keeper clusters defined in the config.
The query must either have a `path =`   condition or a `path IN`  condition set with the `WHERE` clause as shown below. This corresponds to the path of 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' does not exist, an exception will be thrown.

The query `SELECT * FROM system.zookeeper WHERE path IN ('/', '/clickhouse')` outputs data for all children on the `/` and `/clickhouse` node.
If in the specified 'path' collection has does not exist path, an exception will be thrown.
It can be used to do a batch of Keeper path queries.

The query `SELECT * FROM system.zookeeper WHERE path = '/clickhouse' AND zookeeperName = 'auxiliary_cluster'` outputs data in `auxiliary_cluster` ZooKeeper cluster.
If the specified 'auxiliary\_cluster' does not exists, an exception will be thrown.

<h2 id="columns">
  Columns
</h2>

* `name` (String) — The name of the node.
* `path` (String) — The path to the node.
* `value` (String) — Node value.
* `zookeeperName` (String) — The name of default or one of auxiliary ZooKeeper cluster.
* `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 theme={null}
SELECT *
FROM system.zookeeper
WHERE path = '/clickhouse/tables/01-08/visits/replicas'
FORMAT Vertical
```

```text theme={null}
Row 1:
──────
name:           example01-08-1
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
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
```